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

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