using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static void Main(String[] args) {
        string[] tokens_n = Console.ReadLine().Split(' ');
        int n = Convert.ToInt32(tokens_n[0]);
        int m = Convert.ToInt32(tokens_n[1]);
        
        Console.WriteLine(m - 1 + (m) * (n - 1));
    }
}