#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <bits/stdc++.h>
using namespace std;


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