import java.util.Scanner

object Main {
  def main(args:Array[String]): Unit = {
    val sc = new Scanner(System.in)
    val x, a, b = sc.nextInt()

    if (b - a <= 0) {
      println("delicious")
    } else if (b - a <= x) {
      println("safe")
    } else {
      println("dangerous")
    }
  }
}