using System;
namespace App
{
    class Prog
    {
        static void Main(string[] args)
        {
            var a = Console.ReadLine();
            var b = Console.ReadLine();
            var c = Console.ReadLine();

            if (a != b)
            {
                Console.WriteLine(c);
            }
            else
            {
                Console.WriteLine(a);
            }
        }
    }
}