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