#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

long int myFun ( long long int m ,long long int n)
{
    long int result = m-1;
    result = result + ((n-1) * m);
    return result;
}

int main() 
{
    long long int m,n;
    long int result = 0;
    cin >> m >> n;
  
    result = myFun( m , n );
    
    cout << result;
    return 0;
}