import io.StdIn._
 
object Main extends App {
  val Array(n, l) = readLine().split(" ").map(_.toInt)
 
  require(2 <= n && n <= 200)
  require(-100 <= l && l <= 100)

  val a = (n + l)-1
  val b = (l to x).toList
  val c = y.map(Math.abs(_))
  println((y.sum)-z.min)
}