import Data.Array

numOfOne 0 = 0
numOfOne n = mod n 2 + numOfOne (div n 2)
prev i = i - numOfOne i
next i = i + numOfOne i

type Board = Array Int Int
update :: Board -> Board
update b = foldl update' b [first..last] where
  (first,last) = bounds b
  update' b' i =
    let
      b'' = if prev i >= first && b!i+1 < b'!prev i then b'//[(prev i,b!i+1)] else b'
      b''' = if next i <= last && b!i+1 < b''!next i then b''//[(next i,b!i+1)] else b''
    in
      b'''

main = do
  n <- fmap read getLine
  let
    b = (listArray (1,n) $ repeat (n+1))//[(1,1)]
    b' = (iterate update b)!!(n-1)
  putStrLn . show $ if b'!n < n+1 then b'!n else -1