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


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