#include <bits/stdc++.h> 
using namespace std;
using ll =long long;
#define all(v) v.begin(),v.end()
 #define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)


ll mod=1e9+7;

int main() {
   ll A,B;cin>>A>>B;
   ll x=(A+B)/2;
   ll y=abs(A-B)/2; 
   ll s=x-y;
   
  if((A-B)%2==0) {
     cout<<((s+1)%mod*((A+1)%mod)+(s)*(A%mod))%mod<<endl;
  }
  else cout<<(s%mod*((A+1)%mod)+(s+1)%mod*(A%mod))%mod<<endl;
}