using System;

public class Program

{

    public static void Main()

    {

   int i = 0, j = 0;

        int[] arr1 = new int[]{ 7, 7, 8, 8, 9, 1, 1, 4, 2, 2 };

        for (i = 0; i < arr1.Length; i++)

        {

         for (j = 0; j < arr1.Length; j++)

         {

             if (i == j)

             continue;

             if (arr1[j] == arr1[i])

             break;

         }

         if (arr1.Length == j)

         {

             Console.Write (arr1[i] + " ");

         }

        }

    }

​

}