#define here cerr<<"===========================================\n"
#define dbg(x) cerr<<#x<<": "<<x<<endl;
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#define ld double
#define ll long long
#define llinf 100000000000000000LL // 10^17
#define pb push_back
#define popb pop_back
#define fi first
#define sc second
#define endl '\n'
#define pll pair<ll,ll>
#define pld pair<ld,ld>
#define sz(a) (ll)(a.size())
#define all(a) a.begin(),a.end()
#define ceri(a,l,r) {cerr<<#a<<": ";for(ll i_ = l;i_<=r;i_++) cerr<<a[i_]<< " ";cerr<<endl;}
#define daj_mi_malo_vremena ios_base::sync_with_stdio(false);cerr.tie(0);cout.tie(0);cin.tie(0);
using namespace std;
using namespace __gnu_pbds;
#define mod 1000000007
ll add(ll x,ll y){
x+=y;
if(x<0){
x%=mod;
x+=mod;
}else{
if(x>=mod) x%=mod;
}
return x;
}
ll mul(ll a,ll b){
ll ans = (a*b)%mod;
if(ans<0) ans+=mod;
return ans;
}
ll po(ll x,ll y){
if(y==0) return 1LL;
ll ans = po(x,y/2);
ans = mul(ans,ans);
if(y&1) ans = mul(ans,x);
return ans;
}
ll inv(ll x){return po(x,mod-2);}
ll ch(ll x){
return mul(mul(x,x-1),inv(2));
}
#define maxn 3005
ll n,m;
ll dp[maxn][maxn];
void tc(){
cin >> n >> m;
for(ll i = 0;i<maxn;i++) dp[i][0] = dp[0][i] = 1;
for(ll i = 1;i<=n;i++){
for(ll j = 1;j<=m;j++){
dp[i][j] = add(dp[i][j],dp[i-1][j]);
dp[i][j] = add(dp[i][j],mul(dp[i-1][j-1],4*j));
if(i>=2) dp[i][j] = add(dp[i][j],mul(dp[i-2][j-1],mul(j,i-1)));
if(j>=2) dp[i][j] = add(dp[i][j],mul(dp[i-1][j-2],j*(j-1)/2));
}
}
dp[n][m] = add(dp[n][m],-1);
cout<<dp[n][m]<<endl;
}
int main(){
daj_mi_malo_vremena
int t; t = 1;
while(t--){
tc();
}
return 0;
}
