a,b= map(int, input().split())
x=int((1e9)+7)
z=(b*(b-1))//2
z=z*a
z=z*(2+ (b*(a+1)))
z=z//2
print(z%x)#include<bits/stdc++.h>
using namespace std;
#define int long long
int mod=1e9+7;
signed main(){
int a,b;
cin>>a>>b;
int sum1=(((b*(b-1)/2)%mod)*((a*(a+1)/2)%mod))%mod*b;
int sum2=((b*(b-1)/2)%mod)*a;
cout<<(sum1%mod+sum2%mod)%mod<<endl;
}
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