using System;

using System.Collections;

​

public class Program

{

    public static void Main()

    {

        string input = "Racecaar";

        bool output = PalindromePermutation(input);

        Console.WriteLine(output);

    }

​

    public static bool PalindromePermutation(string input)

    {

        bool isPalindrome = true;

        bool hasSingle = false;

        Hashtable letterBook = new Hashtable();

        for (int i = 0; i < input.Length; i++)

        {

            char letterToLower = Char.ToLower(input[i]);

            if (letterToLower.Equals(' '))

            {

                continue;

            }

​

            if (letterBook.ContainsKey(letterToLower))

            {

                letterBook[letterToLower] = (int)letterBook[letterToLower] + 1;

            }

            else

            {

                letterBook[letterToLower] = 1;

            }

        }

​

        foreach (int key in letterBook.Values)

        {

            if (key % 2 != 0)

            {

                if (hasSingle)

                {

                    isPalindrome = false;

                    break;

                }

                else

                {

                    hasSingle = true;

                }

            }

        }

​

        return isPalindrome;

    }

}