using System;

using System.Linq;

using System.Collections.Generic;

using System.Globalization;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

    static  (int vowels, int consonants) CountVowelsConsonants(string input)

    {

        int vowels = 0, consonants = 0;

        string lower = input.ToLower();

        foreach (char c in lower)

        {

            if (char.IsLetter(c))

            {

                if ("aeiou".Contains(c)) vowels++;

                else consonants++;

            }

        }

        return (vowels, consonants);

    }

    static bool AreAnagrams(string str1, string str2)

    {

    return new string(str1.OrderBy(c => c).ToArray()) ==

           new string(str2.OrderBy(c => c).ToArray());

    }

​

    static string ReverseString(string input)

    {

    return new string(input.Reverse().ToArray());

    }

​

    static string RemoveDuplicates(string input)

    {

    return new string(input.Distinct().ToArray());

    }

​

    static string CapitalizeWords(string input)

    {

    return CultureInfo.CurrentCulture.TextInfo.ToTitleCase(input.ToLower());

    }

​

    static string ReplaceSpaces(string input)

    {

    return input.Replace(" ", "-");

    }

​

    static Dictionary<char, int> CountCharacters(string input)

    {

    return input.GroupBy(c => c)

                .ToDictionary(g => g.Key, g => g.Count());

    }   

​

    static string RemoveWhitespace(string input)

    {

    return string.Concat(input.Where(c => !char.IsWhiteSpace(c)));

    }

    static string RemoveSpecialCharacters(string input)

    {

        return new string(input.Where(char.IsLetterOrDigit).ToArray());

    }

    static string ExtractDigits(string input)

    {

        return new string(input.Where(char.IsDigit).ToArray());

    }

    static bool IsNumeric(string input)

    {

        return double.TryParse(input, out _);

    }

​

    static string ReverseWords(string sentence)

    {

    return string.Join(" ", sentence.Split(' ')

        .Select(word => new string(word.Reverse().ToArray())));

    }

​

    static char? FirstNonRepeatingChar(string input)

    {

    return input.GroupBy(c => c)

                .Where(g => g.Count() == 1)

                .Select(g => g.Key)

                .FirstOrDefault();

    }

     static bool IsPalindrome(string input)

    {

    string cleaned = new string(input.Where(char.IsLetterOrDigit).ToArray()).ToLower();

    return cleaned == new string(cleaned.Reverse().ToArray());

    }

​

    static string[] SplitWords(string input)

    {

        return input.Split(' ', StringSplitOptions.RemoveEmptyEntries);

    }

​

​

}