#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {

    long long int n,m,i,j;
    
    
    cin>>n>>m;
    
    
    i=n*m-1;
    
    cout<<i<<endl;
    
    
    return 0;
}