/*
 * Reference: http://lizan.asia/blog/2012/12/11/scala-competitive/
 */

object Main extends App {
  import java.{util => ju}
  import scala.annotation._
  import scala.collection._
  import scala.collection.{mutable => mu}
  import scala.collection.JavaConverters._
  import scala.math._
  val sc = new ju.Scanner(System.in)
  @tailrec
  def  calc(t:Long, n : Long) : Long={
    () match {
     case  _ if n % t == 0 => t
      case _ if 2 * n < t * t => if (n >= 6 && n % 2 == 0) n / 2 else n
      case _ => calc(t + 1, n)
    }
  }
  val n = sc.nextLong
  println(calc(3, n))
}