#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 */   
  unsigned  long long int n,m,ans;
    cin>>n>>m;
    ans=(n*m)-1;
    cout<<ans;
	return 0;
}