main:: IO ()
main = do
    [x,a,b] <- (map read . words) <$> getLine
    putStrLn $ solve (x,a,b)

-- |
--
-- >>> solve (4,3,6)
-- "safe"
--
-- >>> solve (6,5,1)
-- "delicious"
--
-- >>> solve (3,7,22)
-- "dangerous"
solve :: (Int, Int, Int) -> String
solve (x,a,b)
  | b - a >= x + 1  = "dangerous"
  | b - a <= 0  = "delicious"
  | otherwise  = "safe"
