module Main where

import Control.Applicative
import Control.Monad
import Data.List

main :: IO ()
main = do
    [x, a, b] <- fmap read . words <$> getLine :: IO [Int]
    let over = b - a
    case () of
        _ | over <= 0 -> putStrLn "delicious"
          | over <= x -> putStrLn "safe"
          | otherwise -> putStrLn "dangerous"