class A
  def initialize
    n = gets.chomp.to_i
    a = gets.chomp.split(' ').map(&:to_i)

    count = 0

    a.each_cons(3) do |list|
      next if list.uniq.size != list.size

      if list.max == list[1] || list.min == list[1]
        count += 1
      end
    end

    puts count
  end
end

A.new