import java.util.Scanner

object Main extends App {
  val sc = new Scanner(System.in)

  val n = sc.nextInt
  val k = sc.nextInt
  println(Array.fill(n)(sc.nextInt).sorted.reverse.splitAt(k)._1 match {
    case t @ Array(m, _*) => m + ((m > 0) match {
      case true => t.filter(_ > 0).sum - m
      case false => 0
    })
    case _ => 0
  })
}