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

int main()
{
    LI m, n;
    cin >> m >> n;
    if( m > n )  swap( m, n );
    
    if( m == 1 )
        cout << n - 1 << endl;
    else
    {
        cout << m - 1 + (n-1)*m << endl;
    }
    
    return 0;
}