#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: wengsihan
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2072 kb
****************************************************************/