module Main where
import System.Environment (getArgs)


usage = "Fibonacci: I need 1 Parameter \"n\"::Int to tell you the number of recursive calls needed to compute the n-th Fibonacci number"

main :: IO ()
main = do
         args <- getArgs
	       if length args < 1
	          then putStrLn usage
	          else print $ nfib (read (head args)) 
	          

nfib :: Int -> Int
nfib n | n <= 1    = 1
       | otherwise = n1 + n2 + 1
                     where n1 = nfib (n-1)
                           n2 = nfib (n-2)