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