#pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2,avx512f")
#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops")
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define rep(a) rep1(i,a)
#define rep1(i,a) rep2(i,0,a)
#define rep2(i,b,a) for(int i=(b); i<((int)(a)); i++)
#define rep3(i,b,a) for(int i=(b); i>=((int)(a)); i--)
#define all(a) a.begin(),a.end()
#define pii pair<int,int>
#define pb push_back
#define inf 1010000000
//#define inf 4000000000000000000
#define eps 1e-9
#define sz(a) ((int)a.size())
#define pow2(x) (1ll<<(x))
#define ceiling(a,b) (((a)+(b)-1)/(b))
#ifdef i_am_noob
#define bug(...) cerr << "#" << __LINE__ << ' ' << #__VA_ARGS__ << "- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {static int cnt=0;cerr << x << endl;cnt++;if(cnt>1000) exit(0);}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr << x << ", "; _do(y...);}
#else
#define bug(...) 826
#endif
inline char readchar(){
const int maxn=1000000;
static char buf[maxn],*p=buf,*q=buf;
if(p==q&&(q=(p=buf)+fread(buf,1,maxn,stdin))==buf) return EOF;
else return *p++;
}
inline int readint(){
int c=readchar(),x=0,neg=0;
while((c<'0'||c>'9')&&c!='-'&&c!=EOF) c=readchar();
if(c=='-') neg=1,c=readchar();
while(c>='0'&&c<='9') x=(x<<3)+(x<<1)+(c^'0'),c=readchar();
return neg?-x:x;
}
const int Mod=1000000007,Mod2=998244353;
const int MOD=Mod;
const int maxn=3005;
//i_am_noob
int n,m;
ll dp[maxn][maxn];
signed main(){
ios_base::sync_with_stdio(0),cin.tie(0);
#ifdef i_am_noob
freopen("input1.txt","r",stdin);
freopen("output1.txt","w",stdout);
freopen("output2.txt","w",stderr);
#endif
n=readint(),m=readint();
rep(n+1) dp[i][0]=1;
rep(m+1) dp[0][i]=1;
rep(n+1) dp[i][1]=4*i+i*(i-1)/2+1;
rep(m+1) dp[1][i]=4*i+i*(i-1)/2+1;
rep2(i,2,n+1) rep2(j,2,m+1){
dp[i][j]=dp[i-1][j]+4*j*dp[i-1][j-1]+j*(i-1)*dp[i-2][j-1]+j*(j-1)/2*dp[i-1][j-2];
dp[i][j]%=MOD;
}
cout << (dp[n][m]-1+MOD)%MOD << "\n";
return 0;
}
