#include <bits/stdc++.h>
using namespace std;
void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
int n, m;
long long fac[3001], inv[3001], f[3001][3001], g[3001][3001];
const long long mod = 1e9 + 7;
inline long long Bpow(long long inp, long long ind)
{
long long res = 1;
do
{
res = (ind & 1 ? (res * inp) % mod : res);
inp = (inp * inp) % mod;
} while (ind >>= 1);
return res;
}
inline long long C(int k, int n)
{
return (((fac[n] * inv[k]) % mod) * inv[n - k]) % mod;
}
int main()
{
setup();
fac[0] = 1;
inv[0] = Bpow(fac[0], mod - 2);
for (int i = 1; i <= 3000; ++i)
{
fac[i] = (i * fac[i - 1]) % mod;
inv[i] = Bpow(fac[i], mod - 2);
}
cin >> n >> m;
for (int i = 1; i <= n; ++i)
{
for (int j = 1; j <= m; ++j)
{
f[i][j] = (f[i - 1][j - 1] + 1) * 4;
if (2 <= j)
{
f[i][j] += (f[i - 1][j - 2] + 1) * (j - 1);
}
if (2 <= i)
{
f[i][j] += (f[i - 2][j - 1] + 1) * (i - 1);
}
f[i][j] += 4 * (f[i - 1][j - 1] + 1) * (i - 1);
if (2 <= j)
{
f[i][j] += f[i][j - 1];
}
if (2 <= j)
{
f[i][j] += (f[i - 1][j - 2] + 1) * (i - 1) * (j - 1);
}
if (3 <= i)
{
f[i][j] += (f[i - 2][j - 1] + 1) * C(2, i - 1);
}
f[i][j] %= mod;
}
}
cout << f[n][m];
return 0;
}
