using System;

using System.Collections.Generic;

public class Program

{

    public static void Main(){

        Boolean res = IsAnagram("Hello", "hello");

        Console.Write(res);

    }

public static bool IsAnagram(string a1, string a2)

{

    string s1 = a1.ToUpper();

    string s2 = a2.ToUpper();

    if (string.IsNullOrEmpty(s1) || string.IsNullOrEmpty(s2))

        return false;

    if (s1.Length != s2.Length)

        return false;

​

    foreach (char c in s2)

    {

        int ix = s1.IndexOf(c);

        if (ix >= 0)

            s1 = s1.Remove(ix, 1);

        else

            return false;

    }

​

    return string.IsNullOrEmpty(s1);

}

public static bool IsAnagram1(string s1, string s2){

    string  a1 = s1.ToUpper();

    string a2 = s2.ToUpper();

        char[] c1 = a1.ToCharArray();

        List<char> data =new List<char>(c1);

        foreach(char c in a2){

            if(data.Contains(c)){

                data.Remove(c);

            }else{

            return false;

            }

        }

        if(data.Count <= 0){ return true;}

        else return false;

    }

}