#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,a[10001],ans=0,x=0;
	cin>>n; 
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
	}
	a[n+1]=-1;
	a[0]=-1;
	for(int i=2;i<=n;i++)
	{
		if(a[i-1]>=a[i] && a[i+1]>=a[i])
		{
			ans++;
			if(a[i-1]==a[i])
	        {
			    x++;
		      }
		}	
	}
	//cout<<ans<<endl<<x<<endl;
	cout<<ans-x;
	return 0;
}