04. Palindromes

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Extended
{
    class Program
    {
        public static bool IsPalindrome(string inp)
        {
            int min = 0;
            int max = inp.Length - 1;
            while (true)
            {
                if (min > max)
                {
                    return true;
                }
                char a = inp[min];
                char b = inp[max];
                if (a != b)
                {
                    return false;
                }
                min++;
                max--;
            }
        }
        static void Main(string[] args)
        {
            string[] input = Console.ReadLine().Split(new char[]{ ' ', ',', '!', '.', '?' }, StringSplitOptions.RemoveEmptyEntries);
            List<string> l = input.Where(x => IsPalindrome(x) == true).Select(x => x).ToList();
            l.Sort();
            l = l.Distinct().ToList();
            Console.WriteLine(string.Join(", ", l));
        }
    }
}