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: Wrong Answer)

using System;

namespace ConsoleApplication5
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();

            foreach (char letter in input)
            {
                if (Char.IsUpper(letter))
                {
                    Char.ToLower(letter);
                }
                else
                {
                    Char.ToUpper(letter);
                }
            }

            Console.WriteLine(input);
        }
    }
}