#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 int n, m;
    cin >> n;
    cin >> m;
    unsigned long int result = 0;
    result = (n * m) - 1;
    cout << result << endl;
    return 0;
}