using System;
class Program
{
    static void Main()
    {
        var st = Console.ReadLine().ToString();
        var ans = "";

        foreach(var i in st)
        {
            if (char.IsUpper(i))
            {
                ans += char.ToLower(i);
            }
            else if (char.IsLower(i))
            {
                ans += char.ToUpper(i);
            }
        }
        Console.WriteLine(ans);
    }
}