#include <bits/stdc++.h>
using namespace std;
int main(){
	int n,i,h=0;
	cin>>n;
	int a[n];
	for(i=0;i<n;i++){
		cin>>a[i];
	}
	for(i=1;i<n-1;i++){
		if(a[i]>a[i-1]&&a[i]>a[i+1]){
			h++;
		}
	}
	cout<<h;
}
/**************************************************************
	Problem: 1401
	User: linzihang
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/