using System;

public class Program

{

    public static void Main()

    {

        int[]arr=new int[]{3,7,9,12,15};

        int num =int.Parse(Console.ReadLine());

        less(arr,num);

    }

    public static void less(int[]arr,int num )

    {

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

        {

            if (arr[i]<num)

                Console.Write(arr[i]);

        }

    }

}