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.Globalization;
using System.IO;
using System.Linq;
using System.Text;

namespace LogicSummoner
{
    class Program
    {
        static void Main(string[] args)
        {
            var line = Console.ReadLine().Trim();

            var convet = line.Select(l =>
            {
                if ('a' <= l && l <= 'z')
                {
                    return l - 'a' + 'A';
                }
                else if ('A' <= l && l <= 'Z')
                {
                    return l - 'A' + 'a';
                }
                else
                {
                    return l;
                }
            })
            .Select(x => ((char)x).ToString())
            .ToArray();

            System.Console.WriteLine(string.Join("", convet));
        }

        //static StreamReader Console = new StreamReader("input.txt");

        static int GetNumber()
        {
            return int.Parse(Console.ReadLine().Trim());
        }

        static double GetDounble()
        {
            return double.Parse(Console.ReadLine().Trim());
        }

        static int[] GetNumbersInt(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).Select(x => int.Parse(x)).ToArray();
        }

        static long[] GetNumbersLong(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).Select(x => long.Parse(x)).ToArray();
        }

        static double[] GetNumbersDouble(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).Select(x => double.Parse(x)).ToArray();
        }

        static string[] GetStrings(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).ToArray();
        }
    }
}