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