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


int main() {
    int n, m;
    cin >> n >> m;
    cout << n - 1ll + (n) * (m - 1ll) << '\n'; 
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}