solve :: [Int] -> Int
solve xs
  | length xs >= 3 = (if judge (take 3 xs) then 1 else 0)
                   + solve (drop 1 xs)
  | otherwise = 0
  where
    judge :: [Int] -> Bool
    judge xs@[a1,a2,a3] =
        (maximum xs == a2 || minimum xs == a2)
        && a1 /= a3 && a1 /= a2 && a2 /= a3
    judge _ = undefined

main :: IO ()
main = do
    _ <- getLine
    a <- map read . words <$> getLine :: IO [Int]
    print $ solve a