#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 a;
    long b;
    
    cin >> a >> b;
    
    cout << (a*b)-1 << endl;
    
    return 0;
}