module Main where

import System.Environment

infix 8 :+

data Surd5 = !Integer :+ !Integer
                deriving (Eq, Show, Read)

instance Num Surd5 where
   (a :+ b) + (c :+ d) = (a+c) :+ (b+d)
   (a :+ b) - (c :+ d) = (a-c) :+ (b-d)
   (a :+ b) * (c :+ d) = (a*c+b*d) :+ (a*d+(c+d)*b)
   negate (a :+ b) = (-a) :+ (-b)
   signum (a :+ b) = case signum a of
                        0 -> signum b :+ 0
			1 -> case signum b of
			        (-1) -> signum ((2*a-b)^2-5*b^2) :+ 0
				_    -> 1 :+ 0
			_ -> case signum b of
			        1 -> signum (5*b^2-(2*a-b)^2) :+ 0
				_ -> (-1) :+ 0
   abs s = signum s * s
   fromInteger n = n :+ 0

fib :: Integral a => a -> Integer
fib n = let (a:+b) = (0:+1)^n in b

main :: IO ()
main = getArgs >>= mapM_ (print . fib . read)