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


int main() {
    long long n, m, ans;
    
    cin >> n >> m;
    
    //ans += m - 1;
    
    ans += n * m - 1;
    
    
    cout << ans;
    return 0;
}