using System;

public class Program

{

    public static void Main()

    {

    Console.WriteLine("Unesi broj");

​

            double n = Convert.ToDouble(Console.ReadLine());

            double pocetak = 1;

​

            while (n>pocetak)

            {

                if (pocetak % 3 == 0)

                {

                    Console.WriteLine(pocetak);

                    pocetak++;

                }

                else

                {

                    pocetak++;

                }

            }

        if (n % 3 == 0)

        {

            Console.WriteLine(n);

        }           

    }

}