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.Linq;
using System.Text;

namespace AtCoder
{
	class Program
	{
		static void Main(string[] args)
		{
			var Instance = new Question();
			Instance.Exec();
		}
	}

	public class Question
	{
		public void Exec()
		{
			string str = Console.ReadLine();
			StringBuilder builder = new StringBuilder();
			foreach (var item in str) {
				if (char.IsLower(item)) {
					builder.Append(char.ToUpper(item));
				} else if (char.IsUpper(item)) {
					builder.Append(char.ToLower(item));
				} else {
					builder.Append(item);
				}
			}

			Console.WriteLine($"{builder.ToString()}");

			Console.ReadKey();
		}
	}
}