#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
typedef unsigned long long int ull;

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