Description: You are given an array a. Some element of this array ai is a local minimum iff it is strictly less than both of its neighbours (that is, ai < ai - 1 and ai < ai + 1). Also the element can be called local maximum iff it is strictly greater than its neighbours (that is, ai > ai - 1 and ai > ai + 1). Since a1 and an have only one neighbour each, they are neither local minima nor local maxima. An element is called a local extremum iff it is either local maximum or local minimum. Your task is to calculate the number of local extrema in the given array. Input Format: The first line contains one integer n (1 ≤ n ≤ 1000) — the number of elements in array a. The second line contains n integers a1, a2, ..., an (1 ≤ ai ≤ 1000) — the elements of array a. Output Format: Print the number of local extrema in the given array. Note: None