object Main{
 def main(args: Array[String]){
   var in = io.StdIn.readLine().split(' ').map(_.toLong);

   val d:Long = in(0);
   val a:Long = in(1);
   val b:Long = in(2);

   if(a >= b){
       println("delicious");
   }else if(b - a <= d){
       println("safe");
   }else{
       println("dangerous");
   }
 }
}