#include <bits/stdc++.h>
using namespace std;
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii ;
typedef pair<ll, ll> pll ;
typedef vector<pii> vii ;
typedef vector<int> veci ;
typedef vector<pll> vll ;
typedef vector<ll> vecll;
// find_by_order order_of_key
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define F first
#define S second
#define pb push_back
#define endl '\n'
#define Mp make_pair
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " = " << x << endl
#define set_dec(x) cout << fixed << setprecision(x);
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io freopen("in.txt" , "r" , stdin) ; freopen("out.txt" , "w" , stdout);
#define lb lower_bound
#define ub upper_bound
#define for1(n) for(int i=1;i<=n;i++)
#define for0(n) for(int i=0;i<n;i++)
#define forn(n) for(int i=n;i>0;i--)
#define pq priority_queue <pii, vector<pii>, greater<pii>>
const ll mod = 1e9+7 ;// 998244353 ;// 1e9+9;
ll inf=1e18;
const int N=3e3+100,L=21,bs=701,NN=1e6;
int A[N],B[N],C[N],D[N],E[N],n,m,k,q,pre[N],dist[N],vis[N];
vector<int>g[N];
ll dp[N][N];
ll C2(int x){
return x*(x-1)/2;
}
int main(){
fast_io
cin>>n>>m;
for0(N-1)dp[0][i]=dp[i][0]=1;
for1(N-1)dp[i][1]=dp[1][i]=i*4+1+C2(i);
for(int i=2;i<=n;i++){
for(int j=2;j<=m;j++){
dp[i][j]=(dp[i-1][j]+dp[i-1][j-1]*j*4+dp[i-1][j-2]*C2(j)+dp[i-2][j-1]*(i-1)*j)%mod;
}
}
cout<<dp[n][m]-1<<endl;
}
