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;

public class Program
{
	public static void Main(string[] args)
	{
		//var ss = new StreamScanner();
		//---------------------------------
		//????????????int, double, string?????????????????£????????????

		string st = Console.ReadLine();
		char[] chararray = st.ToCharArray();
		for (int i = 0; i < chararray.Length; i++)
		{
			if (char.IsUpper(chararray[i]))
			{
				chararray[i] = char.ToLower(chararray[i]);
			}
			else
			{
				chararray[i] = char.ToUpper(chararray[i]);
			}
		}
		for (int i = 0; i < chararray.Length; i++)
		{
			Console.Write(chararray[i]);
		}
		Console.WriteLine("");
		//int x = ss.Next<int>();
		//double d = ss.Next<double>();
		//string s = ss.Next<string>();

		//?????°???????????????????????¨?????????????????????????????????????????????????´???????
		//int[] array = ss.Next<int>(10);
		//---------------------------------

	}
}
public class StreamScanner
{
	private readonly char[] _c = { ' ' };
	private int _index = -1;
	private string[] _input = new string[0];
	private readonly System.IO.StreamReader _sr = new System.IO.StreamReader(Console.OpenStandardInput());

	public T Next<T>()
	{
		if (_index == _input.Length - 1)
		{
			_index = -1;
			while (true)
			{
				string rl = _sr.ReadLine();
				if (rl == null)
				{
					if (typeof(T).IsClass) return default(T);
					return (T)typeof(T).GetField("MinValue").GetValue(null);
				}
				if (rl != "")
				{
					_input = rl.Split(_c, StringSplitOptions.RemoveEmptyEntries);
					break;
				}
			}
		}
		return (T)Convert.ChangeType(_input[++_index], typeof(T), System.Globalization.CultureInfo.InvariantCulture);
	}

	public T[] Next<T>(int x)
	{
		var ret = new T[x];
		for (var i = 0; i < x; ++i) ret[i] = Next<T>();
		return ret;
	}

	public T[][] Next<T>(int x, int y)
	{
		var ret = new T[y][];
		for (var i = 0; i < y; ++i) ret[i] = Next<T>(x);
		return ret;
	}
}