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

namespace Program
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = Console.ReadLine().Split(' ');
            var A = int.Parse(input[0]);
            var B = int.Parse(input[1]);

            if(A<B)
            {
                Console.WriteLine(B - 2);
            }
            else
            {
                Console.WriteLine(1999999999 - B);
            }
        }
    }
}