/*************************************************************************
    > File Name: hdu5155.cpp
    > Author: ALex
    > Mail: 405045132@qq.com 
    > Created Time: 2015年01月03日 星期六 21时52分09秒
 ************************************************************************/

#include <map>
#include <set>
#include <queue>
#include <stack>
#include <vector>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

const int mod = 1000000007;
long long dp[55][55];
long long C[55][55];

void Combine()
{
	memset (C, 0, sizeof(C));
	C[0][0] = 1;
	for (int i = 1; i <= 50; ++i)
	{
		C[i][0] = 1;
		for (int j = 1; j <= i; ++j)
		{
			if (i == j)
			{
				C[i][j] = 1;
			}
			else if (j == 1)
			{
				C[i][j] = i;
			}
			else
			{
				C[i][j] = C[i - 1][j - 1] + C[i - 1][j];
				C[i][j] %= mod;
			}
//			printf("%d\n", C[i][j]);
		}
	}
}

int main()
{
	Combine();
	int n, m;
	while (~scanf("%d%d", &n, &m))
	{
		memset (dp, 0, sizeof(dp));
		dp[0][0] = 1;
		for (int i = 1; i <= n; ++i)
		{
			for (int j = 0; j <= m; ++j) //前i - 1行亮的列数
			{
				for (int k = 1; k <= m; ++k)//这一行放了k个
				{
					for (int t = 0; j + t <= m; ++t)//这一行亮t个
					{
						if (k - t < 0)
						{
							continue;
						}
						long long tmp = dp[i - 1][j] * C[m - j][t];
						tmp %= mod;
						tmp *= C[j][k - t];
						tmp %= mod;
						dp[i][j + t] += tmp;
						dp[i][j + t] %= mod;
					}
				}
			}
		}
		printf("%lld\n", dp[n][m]);
	}
	return 0;
}