module Main where

data Tree a = Empty | Node a (Tree a) (Tree a) deriving (Show)

inOrder :: Tree a -> [a]
inOrder Empty = []
inOrder (Node a left right) = inOrder left ++ [a] ++ inOrder right

insertNode :: (Ord a) => Tree a -> a -> Tree a
insertNode Empty x = Node x Empty Empty
insertNode (Node a left right) x
    | x < a = Node a (insertNode left x) right
    | x > a = Node a left (insertNode right x)
    | otherwise = Node a left right

main :: IO ()
main =
    interact $
        unwords . map show . inOrder . foldl insertNode Empty . map (read :: String -> Int) . words . (!! 1) . lines