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;

class Sample29
{
    public static void Main()
    {
        var s = Console.ReadLine().Trim();
        var result = "";
        int attempt = s.Length;
        
        //バリデーション
        try
        {
            if(1200 < attempt)
            {
                throw new ArgumentOutOfRangeException();
            }
        }
        catch(ArgumentOutOfRangeException e)
        {
            Console.WriteLine(e.StackTrace);
            Console.WriteLine("文字数が範囲外です。");
            Environment.Exit(0);
        }
            
        //処理
        for (int i = 0; i < attempt; i++)
        {
            if (char.IsUpper(s[i]))
            {
                result += s[i].ToString().ToLower();
            
            }else 
            {
            result += s[i].ToString().ToUpper();
            }
        }
        Console.WriteLine(result);
    }
}