Valera has got a rectangle table consisting of *n* rows and *m* columns. Valera numbered the table rows starting from one, from top to bottom and the columns – starting from one, from left to right. We will represent cell that is on the intersection of row *x* and column *y* by a pair of integers (*x*, *y*).

Valera wants to place exactly *k* tubes on his rectangle table. A tube is such sequence of table cells (*x*<sub class="lower-index">1</sub>, *y*<sub class="lower-index">1</sub>), (*x*<sub class="lower-index">2</sub>, *y*<sub class="lower-index">2</sub>), ..., (*x*<sub class="lower-index">*r*</sub>, *y*<sub class="lower-index">*r*</sub>), that: 
 -  *r* ≥ 2; -  for any integer *i* (1 ≤ *i* ≤ *r* - 1) the following equation |*x*<sub class="lower-index">*i*</sub> - *x*<sub class="lower-index">*i* + 1</sub>| + |*y*<sub class="lower-index">*i*</sub> - *y*<sub class="lower-index">*i* + 1</sub>| = 1 holds; -  each table cell, which belongs to the tube, must occur exactly once in the sequence. 
Valera thinks that the tubes are arranged in a fancy manner if the following conditions are fulfilled: 
 -  no pair of tubes has common cells; -  each cell of the table belongs to some tube. 
Help Valera to arrange *k* tubes on his rectangle table in a fancy manner.
The first line contains three space-separated integers *n*, *m*, *k* (2 ≤ *n*, *m* ≤ 300; 2 ≤ 2*k* ≤ *n*·*m*) — the number of rows, the number of columns and the number of tubes, correspondingly.
#https://codeforces.com/problemset/problem/441/C
#1500

n, m, k = list(map(int, input().split()))
#print(n, m, k)
if n * m < 2 * k:
    print(-1)
else:
    left = 0
    right = m - 1
    up = 0
    down = n - 1
    #螺旋矩阵
    res = []
    while up <= down and left <= right:
        #往右
        if left <= right:
            for i in range(left, right + 1):
                res.append([up, i])
            up += 1
        else:
            break
        #往下
        if up <= down:
            for i in range(up, down + 1):
                res.append([i, right])
            right -= 1
        else:
            break
        #往左
        if left <= right:
            for i in range(right, left - 1, -1):
                res.append([down, i])
            down -= 1
        else:
            break
        #往上
        if up <= down:
            for i in range(down, up - 1, -1):
                res.append([i, left])
            left += 1
        else:
            break
    i = 0
    ans = []
    #print(res)
    while i < k:
        if i != k - 1:
            ans.append([2, res[2 * i][0] + 1, res[2 * i][1] + 1, res[2 * i + 1][0] + 1, res[2 * i + 1][1] + 1])
        else:
            left = len(res) - 2 * i
            j = 2 * i
            tmp = [left]
            for t in range(j, len(res)):
                tmp.append(res[t][0] + 1)
                tmp.append(res[t][1] + 1)
            ans.append(tmp)
        i += 1
    for item in ans:
        print(*item)