codeforce 888A. Local Extrema by李博浩

#include<iostream>
using namespace std;
int main()
{
	int n;cin>>n;
	int a[1010];
	for(int i=0;i<n;i++)
	{
		cin>>a[i];		
	}
	int ans=0;
	for(int i=1;i<n-1;i++)
	{
		if(a[i]>a[i-1]&&a[i]>a[i+1])ans++;
		if(a[i]<a[i-1]&&a[i]<a[i+1])ans++;
	}	
	cout<<ans;
}