q = 10^100

main = readLn >>= print . (/ (fromIntegral q)) . fromIntegral . (aku !!) 

aku :: [Integer]
aku = reverse (apply 100 (\as@(a1:a2:_) -> div (19*a1-12*a2) 4 : as) [3*q,4*q])
 where apply n f x = foldr ($) x (replicate n f)