using System;

public class Program

{

    public static void Main()

    {

        string input="hello everyone";

        string result=Program.RemoveDuplicates(input);

        Console.WriteLine(result);

    }

    private static string RemoveDuplicates(string input)

        {

            string result = "";

            foreach (char c in input)

            {

                if (!result.Contains(c.ToString()) || c == ' ')

                    result += c;

            }

            return result;

        }

}