import Data.List

mm = "1  2  3  4\n5  6  7  8\n9 10 11 12\n13 14 15 16\n17 18 19 20" -- input


ex [] = []
ex m  = (head m) ++ ex (transpose . map reverse . tail $ m)                  

main = putStrLn . concat . intersperse " " $ ex (mme mm)
    where mme m = map reverse $ map words $ lines m

4 3 2 1 5 9 13 17 18 19 20 16 12 8 7 6 10 14 15 11