#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>

typedef long long int ll;
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    ll n , m ;
    
    cin>> n >> m ;
    
    cout<< n*m -1;
    return 0;
}