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