#include <iostream>
#include <vector>
#include <queue>
using namespace std;
#define ll long long
const int N=302,mod=1e9+7;
ll dp[N][N],ndp[N][N];
int main()
{
ll n,m;
cin>>n>>m;
dp[n][m]=1;
for(int i=n;i>=0;i--)
{
for(ll j=m;j>=0;j--)
{
ll w0=(i*(i-1))/2;w0%=mod;
ll w1=(j*(j-1))/2;w1%=mod;
// place nothing
if(i>0)
{
dp[i-1][j]+=dp[i][j];
dp[i-1][j]%=mod;
}
// place one
if(i>0 and j>0)
{
dp[i-1][j-1]+=(dp[i][j]*4*j)%mod;
dp[i-1][j-1]%=mod;
}
if(i>0 and j>1)
{
// place two in row
dp[i-1][j-2]+=(w1*dp[i][j])%mod;
dp[i-1][j-2]%=mod;
}
if(i>1 and j>0)
{
// place two in same column
dp[i-2][j-1]+=((i-1)*dp[i][j]*j)%mod;
}
}
}
ll ans=0;
// for(int i=0;i<=n;i++)
{
for(int j=0;j<=m;j++)
{
ans+=dp[0][j];
ans%=mod;
}
}
// cout<<dp[0][0]<<endl;
cout<<(ans+mod-1)%mod<<endl;
}
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