-- Try yukicoder
-- author: Leonardone @ NEETSDKASU


main = interact $ show . (maximum . (0:) . concat . map (map length . filter (all id) . flip map (takeWhile ((> 0) . length) . zipWith ($) (map drop [0..]) . repeat $ (until ((>= 10^15) . head) (concat . zipWith ($) [return . sum . take 2, id] . repeat) [1, 1])) . zipWith (==)) . zipWith ($) (map drop [0..4]) . repeat) . map read . words