using System;

using System.Text;

public class Program

{

    public static void Main()

    {

        var isPalindrome = CheckIfPalindrome("");

        if(isPalindrome) {

            Console.WriteLine("Palindrome");

        }else {

            Console.WriteLine("Isn't palindrome");

        }

    }

    public static bool CheckIfPalindrome(string sentence){

        sentence = RemoveSpecialCharacters(sentence);

        var sentenceLength = sentence.Length;

        if(sentenceLength == 0) {

            return false;

        }

        for(int i = 0; i < sentenceLength / 2; ++i) {

            if(Char.ToLower(sentence[i]) != Char.ToLower(sentence[sentenceLength - 1 - i])) {

                return false;

            }

        }

        return true;

    }

     public static string RemoveSpecialCharacters(string sentence)

        {

            StringBuilder sb = new StringBuilder();

            foreach (char c in sentence)

            {

                if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'))

                {

                    sb.Append(c);

                }

            }

            return sb.ToString();

        }

}