import Control.Applicative

main :: IO ()
main = solve <$> f >>= putStrLn
  where
    f = map read <$> words <$> getLine

solve :: [Int] -> String
solve [x, a, b]
  | c <= 0 = "delicious"
  | c <= x = "safe"
  | otherwise = "dangerous"
  where
    c = b - a
