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


int main() {
    int n; cin >> n;
    int m; cin >> m;
    
    
    cout << (int64_t)max(n - 1, m - 1) + (int64_t)max(m, n) * min(n - 1, m - 1);
    
    return 0;
}