main :: IO ()
main = readLn >>= putStr . palDecomp ['a'..'z']

palDecomp :: [Char] -> Int -> String
palDecomp (c:cs) 1 = [c]
palDecomp (c:cs) 2 = [c,c]
palDecomp (c:cs) n
  | even n = [c] ++ palDecomp (c:cs) (div n 2) ++ [c]
  | otherwise = [c] ++ palDecomp cs (n-1) ++ [c]