#include <iostream>
#include <vector>
#define ll long long
using namespace std;
const ll M = 1e9 + 7;
ll h, w, f, dp[3001][3001];
int main() {
cin >> h >> w;
for (int i=0; i<=h; ++i) dp[i][0] = 1;
for (ll i=1; i<=h; ++i) {
for (ll j=1; j<=w; ++j) {
if (i != 1) dp[i][j] = dp[i-1][j];
dp[i][j] += dp[i-1][j-1] * (w-j+1) % M * 4 % M;
dp[i][j] %= M;
if (j >= 2) dp[i][j] += dp[i-1][j-2] * ((w-j+2) * (w-j+1) / 2 % M) % M;
dp[i][j] %= M;
if (i >= 2) dp[i][j] += dp[i-2][j-1] * (i-1) % M * (w-j+1) % M;
dp[i][j] %= M;
}
}
for (int j=1; j<=w; ++j) {
f += dp[h][j];
f %= M;
}
cout << f << '\n';
}
