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.Text.RegularExpressions;

namespace AizuOnLine
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();

            for (int i = 0; i < input.Length; i++)
            {
                ChangeStr(input[i]);
            }

            Console.WriteLine("");
        }

        static void ChangeStr(char c)
        {
            if (Regex.IsMatch(c.ToString(), @"[a-z]"))
            {
                Console.Write(c.ToString().ToUpper());
            }
            else
            {
                Console.Write(c.ToString().ToLower());
            }
        }
    }
}