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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    unsigned long int m,n;
    cin >> m >> n;
    if(m==1)
        cout << n-1 << endl;
    else if(n==1)
        cout << m-1 << endl;
    else
        cout << (n-1)+n*(m-1) << endl;
    
    return 0;
}