using System;

public class Program

{

    public static void Main()

    {

        int n, i=1;

        Console.WriteLine("enter n");

        n=Convert.ToInt32(Console.ReadLine());

        while (i<=n)

        {

             if(i%3==0)

             {    

                 Console.WriteLine("i={0}",i);

             }

              i=i+1;

        }

        Console.ReadLine();

    }

}