import Control.Monad
main = do
  n <- readLn
  a <- replicateM n readLn
  putStrLn .show $ solved a []

solved:: [Int] -> [Int] -> Int
solved [] p = length p
solved (a:as) p
  | elem a p = solved as (filter (/= a) p)
  | otherwise = solved as (a:p) 