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.Linq;
using System.Text.RegularExpressions;

namespace ITP1_8
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] sl = Console.ReadLine().ToCharArray().Select(e => e.ToString()).ToArray();
            Regex bre = new Regex(@"^[A-Z]$");
            Regex sre = new Regex(@"^[a-z]$");
            foreach(string s in sl)
                Console.Write(bre.IsMatch(s) ? s.ToLower() :
                              sre.IsMatch(s) ? s.ToUpper() : s);
            Console.WriteLine();
        }
    }
}