#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 */   
    long long n,m;
    bool reduce = false;
    long long res = 0;
    cin >> n >> m;
    if(n > 1) {
        n--;
        res += n;
    }
    if(m > 1) {
        m--;
        res += (n+1) * m;
    }
    cout << res << endl;
    return 0;
}