Problem:
Twin Prime

Prime numbers are widely applied for cryptographic and communication technology.
A twin prime is a prime number that differs from another prime number by 2.
For example, (5, 7) and (11, 13) are twin prime pairs.

In this problem, we call the greater number of a twin prime "size of the twin prime."

Your task is to create a program which reads an integer n and prints a twin prime which has the maximum size among twin primes less than or equals to n

You may assume that 5 ≤ n ≤ 10000.

Input

The input is a sequence of datasets. The end of the input is indicated by a line containing one zero. Each dataset is formatted as follows:

n (integer)

Output

For each dataset, print the twin prime p and q (p < q). p and q should be separated by a single space.

Sample Input

12
100
200
300
0

Output for the Sample Input

5 7
71 73
197 199
281 283

Solution in Haskell (judge verdict: Time Limit Exceeded)

main :: IO ()
main = do
  n <- readLn
  if n == 0
    then return ()
    else do
      putStrLn $ solve n
      main

solve :: Int -> String
solve n = format (findTwin (prime n))
  where
    format :: (Int,Int) -> String
    format (a,b) = (show a) ++ " " ++ (show b)

    findTwin :: [Int] -> (Int,Int)
    findTwin ls = findTwin' (reverse ls)
      where
        findTwin' :: [Int] -> (Int,Int)
        findTwin' (x:y:r)
          | x - y == 2 = (y,x)
          | otherwise = findTwin' (y:r)
    prime :: Int -> [Int]
    prime n = loop [2..n]
      where
        loop :: [Int] -> [Int]
        loop [] = []
        loop (x:xs) = x:(loop (filter (\y -> y `mod` x /= 0) xs))