Bob likes to draw camels: with a single hump, two humps, three humps, etc. He draws a camel by connecting points on a coordinate plane. Now he's drawing camels with *t* humps, representing them as polylines in the plane. Each polyline consists of *n* vertices with coordinates (*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">*n*</sub>, *y*<sub class="lower-index">*n*</sub>). The first vertex has a coordinate *x*<sub class="lower-index">1</sub> = 1, the second — *x*<sub class="lower-index">2</sub> = 2, etc. Coordinates *y*<sub class="lower-index">*i*</sub> might be any, but should satisfy the following conditions:
 -  there should be *t* humps precisely, i.e. such indexes *j* (2 ≤ *j* ≤ *n* - 1), so that *y*<sub class="lower-index">*j* - 1</sub> &lt; *y*<sub class="lower-index">*j*</sub> &gt; *y*<sub class="lower-index">*j* + 1</sub>, -  there should be precisely *t* - 1 such indexes *j* (2 ≤ *j* ≤ *n* - 1), so that *y*<sub class="lower-index">*j* - 1</sub> &gt; *y*<sub class="lower-index">*j*</sub> &lt; *y*<sub class="lower-index">*j* + 1</sub>, -  no segment of a polyline should be parallel to the *Ox*-axis, -  all *y*<sub class="lower-index">*i*</sub> are integers between 1 and 4. 
For a series of his drawings of camels with *t* humps Bob wants to buy a notebook, but he doesn't know how many pages he will need. Output the amount of different polylines that can be drawn to represent camels with *t* humps for a given number *n*.
The first line contains a pair of integers *n* and *t* (3 ≤ *n* ≤ 20, 1 ≤ *t* ≤ 10).
6 1
6
4 2
0
3 1
14
3 2
0
3 3
0
3 10
0
4 1
22
4 3
0
4 9
0
5 1
16
5 2
70
5 3
0
5 5
0
5 9
0
5 10
0
6 1
6
6 2
232
6 3
0
6 4
0
6 10
0
19 1
0
19 2
0
19 3
1
19 4
32632
19 5
4594423
19 6
69183464
19 7
197939352
19 8
109824208
19 9
5846414
19 10
0
20 1
0
20 2
0
20 3
0
20 4
12628
20 5
3715462
20 6
96046590
20 7
468541040
20 8
503245466
20 9
90700276
20 10
0
# LUOGU_RID: 133310393
#include<bits/stdc++.h>
using namespace std;
int x,y,a[21][11];
int main() {
	cin>>x>>y;
	a[3][1]=14;a[4][1]=22;a[5][1]=16;a[5][2]=70;a[6][1]=6;a[6][2]=232;a[7][1]=1;a[7][2]=380;a[7][3]=353;a[8][2]=396;a[8][3]=1786;a[9][2]=284;a[9][3]=4500;a[9][4]=1782;a[10][2]=142;a[10][3]=7414;a[10][4]=12122;a[11][2]=48;a[11][3]=8849;a[11][4]=41160;a[11][5]=8997;a[12][2]=10;a[12][3]=8028;a[12][4]=92226;a[12][5]=76878;a[13][2]=1;a[13][3]=5658;a[13][4]=152140;a[13][5]=328222;a[13][6]=45425;a[14][3]=3112;a[14][4]=195420;a[14][5]=928494;a[14][6]=467292;a[15][3]=1322;a[15][4]=201744;a[15][5]=1947581;a[15][6]=2402980;a[15][7]=229347;a[16][3]=422;a[16][4]=170444;a[16][5]=3213988;a[16][6]=8205152;a[16][7]=2758896;a[17][3]=96;a[17][4]=118912;a[17][5]=4322956;a[17][6]=20852648;a[17][7]=16594160;a[17][8]=1157954;a[18][3]=14;a[18][4]=68640;a[18][5]=4846524;a[18][6]=41920210;a[18][7]=66357900;a[18][8]=15946870;a[19][3]=1;a[19][4]=32632;a[19][5]=4594423;a[19][6]=69183464;a[19][7]=197939352;a[19][8]=109824208;a[19][9]=5846414;a[20][4]=12628;a[20][5]=3715462;a[20][6]=96046590;a[20][7]=468541040;a[20][8]=503245466;a[20][9]=90700276;
	cout<<a[x][y];
	return 0;
} 