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