#include <bits/stdc++.h>
#define FOR(i,x,n) for(int i=x; i<n; i++)
#define F0R(i,n) FOR(i,0,n)
#define ROF(i,x,n) for(int i=n-1; i>=x; i--)
#define R0F(i,n) ROF(i,0,n)
#define WTF cout << "WTF" << endl
#define IOS ios::sync_with_stdio(false); cin.tie(0)
#define F first
#define S second
#define pb push_back
#define ALL(x) x.begin(), x.end()
#define RALL(x) x.rbegin(), x.rend()
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef vector<int> VI;
typedef vector<LL> VLL;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
const int MAXN = 3000 + 7;
const int ALPHA = 27;
const int INF = 1e9 + 7;
const int MOD = 1e9 + 7;
const int LOG = 22;
int n, m;
LL fact[MAXN << 1], inv_fact[MAXN << 1];
LL dp[MAXN << 1], f[MAXN][MAXN];
inline LL pw(LL a, LL b) {
LL res = 1;
for(; b; b >>= 1, a = a * a % MOD)
if (b & 1) res = res * a % MOD;
return res;
}
inline LL nCr(int nn, int rr) {
if (nn < rr || rr < 0) return 0;
return (fact[nn] * inv_fact[rr] % MOD) * inv_fact[nn - rr] % MOD;
}
void precalc() {
fact[0] = 1;
FOR(i, 1, (MAXN << 1)) fact[i] = fact[i - 1] * i % MOD;
inv_fact[(MAXN << 1) - 1] = pw(fact[(MAXN << 1) - 1], MOD - 2);
R0F(i, (MAXN << 1) - 1) inv_fact[i] = inv_fact[i + 1] * (i + 1) % MOD;
//cout << pw(8, MOD - 2) << ' ' << inv_fact[8] << endl;
dp[0] = 1;
for(int i = 2; i < (MAXN << 1); i += 2)
dp[i] = nCr(i, 2) * dp[i - 2] % MOD;
F0R(p, MAXN) f[p][0] = f[0][p] = 1;
FOR(p, 1, MAXN) {
f[p][0] = 1;
FOR(q, 1, MAXN) f[p][q] = (f[p - 1][q] + 4ll * q * f[p - 1][q - 1]) % MOD;
}
return;
}
int main() {
IOS;
precalc();
cin >> n >> m;
LL ans = 0;
F0R(x, n + 1) F0R(y, m + 1) {
if (n - 2 * x - y < 0 || m - x - 2 * y < 0) continue;
ans = (ans + (((((nCr(n, 2 * x) * nCr(m, 2 * y) % MOD) * nCr(m - 2 * y, x) % MOD) * nCr(n - 2 * x, y) % MOD) * f[n - 2 * x - y][m - x - 2 * y] % MOD) * dp[2 * x] % MOD) * dp[2 * y] % MOD);
}
cout << (ans - 1 + MOD) % MOD;
}
