import java.util.Scanner

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

  val x = sc.nextInt
  val a = sc.nextInt
  val b = sc.nextInt

  val res =
    if(b < a) "delicious"
    else if(a <= b && b < a + x) "safe"
    else "dangerous"

  println(res)
}