#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 n, m;
    cin >> n >> m;
    long res;
    
    res = n * m - 1;
    
    cout << res;
    
    return 0;
}