#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ar array
const int mxN=3000, M=1e9+7;
int n, m;
ll dp[mxN+1][mxN+1];
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for (int i=0; i<=max(n, m); ++i)
dp[0][i]=dp[i][0]=1;
for (int i=1; i<=n; ++i)
for (int j=1; j<=m; ++j) {
// two tents on row 1
dp[i][j]=dp[i-1][j];
if (j>=2)
dp[i][j]=(dp[i][j]+dp[i-1][j-2]*j*(j-1)/2)%M;
dp[i][j]=(dp[i][j]+dp[i-1][j-1]*4*j)%M;
if (i>=2)
dp[i][j]=(dp[i][j]+dp[i-2][j-1]*j*(i-1))%M;
}
cout << (dp[n][m]-1+M)%M;
return 0;
}
