#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>

using namespace std;


int main(){
	int n;
	cin >> n;
	vector<int> a(n);
	for(int i=0; i<n; i++){
		cin >> a[i];
	}

	deque<int> dq;
	dq.push_back(a[0]);
	dq.push_back(a[1]);

	int ans = 0;
	for(int i=2; i<n; i++){
		dq.push_back(a[i]);
		if(dq[0] == dq[1] || dq[1] == dq[2] || dq[0] == dq[2]){
			
		}else{
			priority_queue<int> pq(dq.begin(), dq.end());
			pq.pop();
			if(pq.top() == dq[0] || pq.top() == dq[2]){
				ans++;
			}
		}
		dq.pop_front();
	}
	cout << ans << endl;
	return 0;
}