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


int main() {
    
        long int n = 0;
        long int m = 0;
        long int ans = 0;
        cin>>n;
        cin>>m;
        ans = (n-1)*m + m -1;
        cout<<ans;
 
    return 0;
}