using System;
using System.Collections.Generic;
using System.IO;
class Solution {
    static void Main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
        string [] input = Console.ReadLine().Split(' ');
        long n = Convert.ToInt64(input[0]) - 1;
        long m = Convert.ToInt64(input[1]) - 1;
        long result = n + m + n*m ;
        Console.WriteLine(result);
    }
}