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 */
        
        long result = 0;
        string[] arrS = Console.ReadLine().Split(' ');
        Int64[] arr = Array.ConvertAll(arrS,Int64.Parse);
        
        long rows = arr[0];
        long columns = arr[1];
        
        if(rows == 1)
            result = columns - 1;
        else if(columns == 1)
            result = rows - 1;
        else
        {
            long min = Math.Min(rows,columns);
            result = (min - 1) + (Math.Max(rows,columns) - 1) * min;
        }
            
        Console.WriteLine(result);   
        
    }
}