using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

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 input = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        Console.WriteLine(Cuts(input[0],input[1]));
    }
    
    static long Cuts(int width, int height)
    {
        if(width < height)
        {
            return Cuts(height,width);    
        }
        else if(height == 1)
        {
            return width-1;
        }
        else    
        {
            if(height % 2 != 0)
            {
                return Cuts(width, (int)Math.Ceiling(height / 2.0)) + Cuts(width, (int)Math.Floor(height / 2.0)) + 1;
            }
            else
            {
                return Cuts(width, height / 2)*2 + 1;
            }    
        }
    }
}