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 */
        
          var line1 = Console.ReadLine().Split(' ');
            var n = Convert.ToUInt64(line1[0]);
            var m = Convert.ToUInt64(line1[1]);

            var ans = (n - 1) + n * (m - 1);
            
        
            Console.WriteLine(ans);
    }
}