import System.Environment (getArgs)
import Data.List (foldl')

fibs :: (Enum b, Integral t, Num b) => b -> (t, t)
fibs n = foldl' (\(b, a) _ -> (a `seq` (a + b) `mod` 10, b)) (1, 0) [1 .. (n-1)]

main :: IO()
main = do
    [a] <- getArgs
    print . fst .fibs $ read a