class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] candidate = Array.ConvertAll(Console.ReadLine().Split(' '), num => int.Parse(num));
            int count = 0;
            for(int i = 0; i < n - 2; i++)
            {
                int[]judge = new int[3];
                Array.Copy(candidate, i, judge, 0, 3);
                if (JudgeKadomatsu(judge))
                {
                    count++;
                }
            }
            Console.WriteLine(count);
        }

        private static bool JudgeKadomatsu(int[] judge)
        {
            bool clearFlg = true;
            if (judge[0] == judge[1] || judge[0] == judge[2] || judge[1] == judge[2])
            {
                clearFlg = false;
            }
            if (clearFlg && !(judge.Max() == judge[1] || judge.Min() == judge[1]))
            {
                clearFlg = false ;
            }
            return clearFlg;
        }
    }