---

#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    
    int numbers[100];
    
    for (int i = 0; i < n; i++) {
        cin >> numbers[i];
    }
    
    int count = 0;
    
    for (int i = 1; i < n - 1; i++) {
        if (numbers[i-1] < numbers[i] && numbers[i+1] < numbers[i]) {
            count++;
        }
    }
    
    cout << count << endl;
    
    return 0;
}