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]) - 1 ;
        int m = Convert.ToInt32(tokens_n[1]);
        
        int result;
        result = n * m;
        
        Console.WriteLine(result);
    }
    
   
}