#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,i,l=0; 
    cin>>n;
    int j[n];
    for(i=0;i<n;i++){
        cin>>j[i];
    }
    for(i=1;i<n-1;i++){
        if(j[i]>j[i-1]&&j[i]>j[i+1]){
            l++;
        }
    }
    cout<<l;
}
/**************************************************************
	Problem: 1401
	User: yangjunwen
	Language: C++
	Result: Accepted
	Time:18 ms
	Memory:2072 kb
****************************************************************/