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.Linq;
using System.Collections.Generic;

namespace ConsoleApp3
{
    class Program
    {
        static void Main(string[] args)
        {
            string line = Console.ReadLine();
            List<char> c1 = new List<char>();

            for(int i = 0; i < line.Length; i++)
            {
                if (char.IsUpper(line[i]))
                {
                    c1.Add(char.ToLower(line[i]));
                }
                else if (char.IsLower(line[i]))
                {
                    c1.Add(char.ToUpper(line[i]));
                }
                else
                {
                    c1.Add(line[i]);
                }
            }

            foreach (char item in c1)
            {
                Console.Write(item);
            }
            Console.WriteLine();
        }

    }
}