import Control.Applicative ((<$>))

minNumOfOps :: Integral a => a -> [a] -> a
minNumOfOps = foldr (\x t -> if x == t then t - 1 else t)

main :: IO ()
main = do
    n <- readLn :: IO Int
    xs <- fmap read . words <$> getLine :: IO [Int]
    print $ minNumOfOps n xs