import qualified Data.ByteString.Char8 as C
import Data.List
import Data.Ord
import Control.Monad


r' :: IO [Int]
r'  =   unfoldr    (C.readInt . C.dropWhile (==' ')) <$> C.getLine


main = do 
    [x,a,b] <- r'
    putStrLn $ if b<=a then "delicious" else if b-a <= x then "safe" else "dangerous"
