#include<iostream>
#include<math.h>
using namespace std;
int main()
{
int n, a, x; // n=tedad , a=jame aadad , x=adad avval majmooeh;
cout<<"\n agar donbale zoj ast adad 0, va agar fard ast adad 1 ra vared konid \n";
cin>> x;
cout<< "tedad jomalat(n) ra vared konid \n";
cin>> n;
a= n*(x+n-1);
cout<< a;
return 0;
}