{-# OPTIONS_GHC -O2 -funbox-strict-fields #-}
import           Control.Monad (replicateM)
import           Data.List     (nub)
main :: IO ()
main = print =<< solve <$> getInput

getInput :: IO [Int]
getInput = do
  n <- readLn
  replicateM n readLn

solve :: [Int] -> Int
solve = length . nub
