import Prelude

expire :: Int->Int->Int->String
expire x a b
	|b<=a 	= "delicious"
	|b>=a && b<=(a+x) = "safe"
	|otherwise = "dangerous"
 
main :: IO ()
main = do
    -- スペース区切り整数の入力
    [x, a, b] <- map read . words <$> getLine
    -- 出力
    putStrLn $ expire x a b

