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


int main() {
    long long int n, m;
    
    cin >> n ;
    cin >> m;

    if( n == 1 )
        cout << (m-1);
    else if( m == 1 )
        cout << (n-1);
    else
    cout << (m-1)+(n-1)*(m) ;
    
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}