#include <iostream>

using namespace std;

int main()
{
    int n, v[100005];
    cin >> n;
    for(int i = 1; i <= n; ++i)
        cin >> v[i];
    int nr = 0;
    for(int i = 2; i < n; ++i)
        if(v[i]>v[i-1] && v[i]>v[i+1])
            ++nr;
    cout << nr;
}