Problem:
﻿Score: 100 points

Problem Statement

In AtCoder city, there are five antennas standing in a straight line. They are called Antenna A, B, C, D and E from west to east, and their coordinates are a, b, c, d and e, respectively.

Two antennas can communicate directly if the distance between them is k or less, and they cannot if the distance is greater than k.

Determine if there exists a pair of antennas that cannot communicate directly.

Here, assume that the distance between two antennas at coordinates p and q (p < q) is q - p.

Constraints

a, b, c, d, e and k are integers between 0 and 123 (inclusive).

a < b < c < d < e

Input

Input is given from Standard Input in the following format:

a
b
c
d
e
k

Output

Print :( if there exists a pair of antennas that cannot communicate directly, and print Yay! if there is no such pair.

Sample Input 1

1
2
4
8
9
15

Sample Output 1

Yay!

In this case, there is no pair of antennas that cannot communicate directly, because:

the distance between A and B is 2 - 1 = 1

the distance between A and C is 4 - 1 = 3

the distance between A and D is 8 - 1 = 7

the distance between A and E is 9 - 1 = 8

the distance between B and C is 4 - 2 = 2

the distance between B and D is 8 - 2 = 6

the distance between B and E is 9 - 2 = 7

the distance between C and D is 8 - 4 = 4

the distance between C and E is 9 - 4 = 5

the distance between D and E is 9 - 8 = 1

and none of them is greater than 15. Thus, the correct output is Yay!.

Sample Input 2

15
18
26
35
36
18

Sample Output 2

:(

In this case, the distance between antennas A and D is 35 - 15 = 20 and exceeds 18, so they cannot communicate directly.
Thus, the correct output is :(.

Solution in Haskell (GHC 7.10.3) (judge verdict: Wrong Answer)

import           Control.Monad
import           Control.Monad.ST
import qualified Data.Array                  as A
import qualified Data.Array.Unboxed          as AU
import qualified Data.ByteString.Char8       as BS
import           Data.Char
import           Data.List
import           Data.Maybe
import           Data.Ord
import           Data.Time
import qualified Data.Vector                 as V
import qualified Data.Vector.Mutable         as VM
import qualified Data.Vector.Unboxed         as VU
import qualified Data.Vector.Unboxed.Mutable as VUM

readIntegers :: IO [Integer]
readIntegers = map (fst . fromJust . BS.readInteger) . BS.words <$> BS.getLine

readIntegerLists :: Int -> IO [[Integer]]
readIntegerLists n =
  replicateM n (map (fst . fromJust . BS.readInteger) . BS.words <$> BS.getLine)

readInts :: IO [Int]
readInts = map (fst . fromJust . BS.readInt) . BS.words <$> BS.getLine

readIntLists :: Int -> IO [[Int]]
readIntLists n =
  replicateM n (map (fst . fromJust . BS.readInt) . BS.words <$> BS.getLine)

readStrings :: IO [String]
readStrings = map BS.unpack . BS.words <$> BS.getLine

readStringLists :: Int -> IO [[String]]
readStringLists n = replicateM n (map BS.unpack . BS.words <$> BS.getLine)

toPair :: [a] -> (a, a)
toPair [x, y] = (x, y)

main :: IO ()
main = do
  path <- replicateM 6 $ read <$> getLine
  putStrLn $ solve path
  return ()

solve :: [Int] -> String
solve path
  | last path < last sorted - head sorted = ":("
  | otherwise = "Yey!"
  where
    sorted = sort $ init path
-- solve n w vw = f 0 w
--   where
--     items = VU.fromList vw
--     f i cap
--       | i == n = 0
--       | snd (items VU.! i) > cap = f (i + 1) cap
--       | otherwise =
--         max
--           (memo A.! (i + 1, cap))
--           (memo A.! (i + 1, cap - snd (items VU.! i)) + fst (items VU.! i))
--     memo =
--       A.array
--         ((0, 0), (n, w))
--         [((n', w'), f n' w') | n' <- [0 .. n], w' <- [0 .. w]]