Mahmoud was trying to solve the vertex cover problem on trees. The problem statement is:

Given an undirected tree consisting of *n* nodes, find the minimum number of vertices that cover all the edges. Formally, we need to find a set of vertices such that for each edge (*u*, *v*) that belongs to the tree, either *u* is in the set, or *v* is in the set, or both are in the set. Mahmoud has found the following algorithm:
 -  Root the tree at node 1. -  Count the number of nodes at an even depth. Let it be *evenCnt*. -  Count the number of nodes at an odd depth. Let it be *oddCnt*. -  The answer is the minimum between *evenCnt* and *oddCnt*. 
The depth of a node in a tree is the number of edges in the shortest path between this node and the root. The depth of the root is 0.

Ehab told Mahmoud that this algorithm is wrong, but he didn't believe because he had tested his algorithm against many trees and it worked, so Ehab asked you to find 2 trees consisting of *n* nodes. The algorithm should find an incorrect answer for the first tree and a correct answer for the second one.
The only line contains an integer *n* (2 ≤ *n* ≤ 10<sup class="upper-index">5</sup>), the number of nodes in the desired trees.
In the first sample, there is only 1 tree with 2 nodes (node 1 connected to node 2). The algorithm will produce a correct answer in it so we printed  - 1 in the first section, but notice that we printed this tree in the second section.

In the second sample:

In the first tree, the algorithm will find an answer with 4 nodes, while there exists an answer with 3 nodes like this: <img class="tex-graphics" src="https://espresso.codeforces.com/fb4efe76f0a74395fe77f22da2dbd2a3340f8b2a.png" style="max-width: 100.0%;max-height: 100.0%;"/> In the second tree, the algorithm will find an answer with 3 nodes which is correct: <img class="tex-graphics" src="https://espresso.codeforces.com/700db299c05ae94849f44b93e8240d375a0fe05f.png" style="max-width: 100.0%;max-height: 100.0%;"/>
2
-1
1 2
8
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 2
1 3
1 4
1 5
1 6
1 7
1 8
99
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
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1 40
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1 45
1 46
1 47
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1 49
1 50
1 51
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1 53
1 54
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1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
100
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
100000
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
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1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
3212
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
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1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
54321
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
54320
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
3
-1
1 2
1 3
4
-1
1 2
1 3
1 4
5
-1
1 2
1 3
1 4
1 5
6
1 2
1 3
1 4
2 5
2 6
1 2
1 3
1 4
1 5
1 6
7
1 2
1 3
1 4
2 5
2 6
1 7
1 2
1 3
1 4
1 5
1 6
1 7
67575
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
99999
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
2048
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
2047
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
2049
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
10101
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
11
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
13
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
21
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
31
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
43
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
57
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
...
73
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
...
91
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
111
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
133
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
157
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
183
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
211
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
241
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
273
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
307
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
343
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
381
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
421
1 2
1 3
1 4
2 5
2 6
1 7
1 8
1 9
1 10
1 11
1 12
1 13
1 14
1 15
1 16
1 17
1 18
1 19
1 20
1 21
1 22
1 23
1 24
1 25
1 26
1 27
1 28
1 29
1 30
1 31
1 32
1 33
1 34
1 35
1 36
1 37
1 38
1 39
1 40
1 41
1 42
1 43
1 44
1 45
1 46
1 47
1 48
1 49
1 50
1 51
1 52
1 53
1 54
1 55
1 56
1 57
1 58
1 59
1 60
1 61
1 62
1 63
1 64
1 65
1 66
1 67
1 68
1 69
1 70
1 71
1 72
1 73
1 74
1 75
1 76
1 77
1 78
1 79
1 80
1 81
1 82
1 83
1 84
1 85
1 86
1 87
1 8...
import sys
input = sys.stdin.readline

n = int(input())
if n < 6:
    print(-1)
else:
    print(1, 2)
    print(2, 3)
    print(2, 4)
    for i in range(5, n+1):
        print(1, i)
for i in range(2, n+1):
    print(1, i)