import io.{StdIn => in}

object Main extends App {
  val Array(w, a, b) = in.readLine.split(" ").map(_.toInt)
  val (s, l) = if(a < b) (a, b) else (b, a)
  val res = l - (s + w)
  val ans = if(res < 1) 0 else res
  println(ans)
}