#include<bits/stdc++.h>
using namespace std;
#define ll long long int 
int main()
{
  
        ll n,m;
        cin>>n>>m;
        ll p=n*m;
        for(int i=1;i<min(n,m);i++)
        {
            p+=((n-i)*(m-i));
        }
        cout<<p<<endl;
    


}