using System;

​

//Implement a method which receives as parameter a list of integer elements and returns a sequence in which 

//the duplicated numbers have been removed and where the elements are ordered following the order of the first appearance of each element in the original list.

//For example (5, 5, 1, 3, 1, 2) -> (5,1,3,2)

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}