#include <bits/stdc++.h> //Andrei Alexandru a.k.a Sho10
#define ll long long
#define double long double
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#define all(a) (a).begin(), (a).end()
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define pi pair
#define rc(s) return cout<<s,0
#define endl '\n'
#define mod (10*10*10*10*10*10*10*10*10+7)
#define PI 3.14159265359
#define MAXN 100005
#define INF 1000000005
#define LINF 1000000000000000005ll
#define CODE_START ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
ll n,m,dp[3005][3005];
int32_t main(){
CODE_START;
cin>>n>>m;
for(ll i=0;i<=n;i++)
{
for(ll j=0;j<=m;j++)
dp[i][j]=1;
}
for(ll i=1;i<=n;i++)
{
for(ll j=1;j<=m;j++)
{
dp[i][j]=dp[i-1][j];
if(j>=2){
dp[i][j]+=dp[i-1][j-2]*j*(j-1)/2;
}
if(i>=2){
dp[i][j]+=dp[i-2][j-1]*j*(i-1);
}
dp[i][j]+=4*j*dp[i-1][j-1];
dp[i][j]%=mod;
}
}
cout<<dp[n][m]-1<<endl;
}
