using System;

public class Program

{

    public static void Main()

    {

        string anyno = "1 2 3 3 4 4 8 2 1";

        int count;

        char[] str = anyno.ToCharArray();

         for( int i= 0; i<str.Length; i++)

         {

             count= 1;

         for( int j= i+1; j<str.Length; j++)

         {

             if(str[i] == str[j] && str[i] != '0')

             {

                 count++;

                 str[j] = '0';

             }

         }

             if(count == 1 && str[i] != '0')

             Console.WriteLine(str[i]);

         }

    }

}