#include <bits/stdc++.h>
using namespace std;
#define x first
#define y second
#define ll long long
#define pi pair<int,int>
#define pl pair<ll,ll>
#define pd pair<double,double>
#define ld long double
#define pld pair<ld,ld>
#define lg length()
#define sz size()
#define vi vector<int>
#define vl vector<ll>
#define vp vector<pi>
#define vpl vector<pl>
#define pb push_back
#define INF 1000000005
#define LINF 1000000000000000005
int n,m;
ll mod=1e9+7,dp[3005][3005];
int32_t main(){
/*seed_seq seq{
(uint64_t) chrono::duration_cast<chrono::nanoseconds>(chrono::high_resolution_clock::now().time_since_epoch()).count(),
(uint64_t) __builtin_ia32_rdtsc(),
(uint64_t) (uintptr_t) make_unique<char>().get()
};
mt19937 rng(seq);*/
ios_base :: sync_with_stdio(0); cin.tie(); cout.tie();
#ifdef LOCAL_DEFINE
ifstream cin("input.in");
#endif
cin >> n >> m;
for(int j=0;j<=m;j++) dp[0][j]=1;
for(int j=0;j<=n;j++) dp[j][0]=1;
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
if(i>1 && j>1) dp[i][j]=dp[i][j-1]+dp[i-1][j-1]*i*4+dp[i-2][j-1]*i*(i-1)/2+dp[i-1][j-2]*i*(j-1);
else if(i>1) dp[i][j]=dp[i][j-1]+dp[i-1][j-1]*i*4+dp[i-2][j-1]*i*(i-1)/2;
else if(j>1) dp[i][j]=dp[i][j-1]+dp[i-1][j-1]*i*4+dp[i-1][j-2]*i*(j-1);
else dp[i][j]=dp[i][j-1]+dp[i-1][j-1]*i*4;
dp[i][j]%=mod;
}
}
cout << (dp[n][m]-1+mod)%mod;
}
