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