#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 int m,n,a;
    cin>>m>>n;
    a=m*n;
    cout<<a-1;
    
    return 0;
}