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


int main() {
    long long a, b;
    cin >> a >> b;
    if(a > b)  swap(a, b);
    
    if(a == 1) return cout << b - 1 << '\n', 0;

    cout << (b - 1) * a + a - 1 << '\n';
    
    return 0;
}