use std::io;

fn main() {
  let mut buf = String::new();
  io::stdin().read_line(&mut buf).ok();

  let mut buf = String::new();
  io::stdin().read_line(&mut buf).ok();
  let a: Vec<u16> = buf
    .trim()
    .split_whitespace()
    .map(|e| e.parse().ok().unwrap())
    .collect();

  let mut result = 0;

  for v in a.windows(3) {
    if v[0] != v[1] && v[1] != v[2] && v[2] != v[0] {
      let &max = v.iter().max().unwrap();
      let &min = v.iter().min().unwrap();

      if v[1] == max || v[1] == min {
        result += 1;
      }
    }
  }
  println!("{}", result);
}