import Control.Monad

loop :: Int -> [String] -> Int -> IO Int
loop 0 xs m = return m
loop n xs m = do
  s <- getLine
  if elem s xs
    then loop (n-1) xs m
    else loop (n-1) (s:xs) (m+1)

main :: IO ()
main = do
 n <- readLn
 m <- loop n [] 0
 print m