#include<iostream>
using namespace std;
int a[10005];
int main() {
	int n;
	cin >> n;
	int cnt = 0;
	for (int i = 1; i <= n; i++)cin >> a[i];
	for (int i = 2; i <= n - 1; i++) {
		if (a[i - 1] > a[i]) {
			if (a[i] <= a[i + 1]) {
				cnt++;
			}
	  }
	}
	cout << cnt;
}