Problem:
Toggling Cases

Write a program which converts uppercase/lowercase letters to lowercase/uppercase for a given string.

Input

A string is given in a line.

Output

Print the converted string in a line. Note that you do not need to convert any characters other than alphabetical letters.

Constraints

The length of the input string < 1200

Sample Input

fAIR, LATER, OCCASIONALLY CLOUDY.

Sample Output

Fair, later, occasionally cloudy.

Solution in C# (judge verdict: Accepted)

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

namespace AizuOnline
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            //var x = Console.ReadLine().Split(',');
            var x = Console.ReadLine();

            var a = "abcdefghijklmnopqrstuvwxyz";
            var A = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            var o = string.Empty;
            foreach (var s in x.ToCharArray())
            {
                if (a.Contains(s))
                {
                    o += Char.ToUpper(s);
                }
                else if (A.Contains(s))
                {
                    o += Char.ToLower(s);
                }
                else
                {
                    o += s;
                }
            }
            Console.WriteLine(o);

            Console.ReadLine();
        }
    }
}