#include<iostream>
using namespace std;
int main()
 {unsigned long long int n,m;
    cin>>n>>m;
    if(m==1)
        cout<<n-1<<endl;
  else if(n==1)
      cout<<m-1<<endl;
  else if(n>m)
      cout<<(m-1)+m*(n-1)<<endl;
      else
      cout<<(n-1)+n*(m-1)<<endl;
    return 0;
}