import io.StdIn.readLine
object Main extends App {
  val Array(x, a, b) = readLine.split(" ").map(_.toInt)
  println(solve(x, a, b))

  def solve(x: Int, a: Int, b: Int) = {
    if (a >= b) "delicious"
    else if ((b - a) <= x) "safe"
    else "dangerous"
  }
}
