using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukicoder_333 {
    class Program {
        static void Main(string[] args) {
            int[] h = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
            if (h[0] < h[1]) {
                Console.WriteLine(h[1] - 2);
            } else {
                Console.WriteLine(2000000000 - h[1] - 1);
            }
            Console.ReadLine();
        }
    }
}