#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 n,m;
    scanf("%ld %ld",&n,&m);
    printf("%ld",n*m-1);
    return 0;
}