#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,i,j,a[10],s=0,d;
    cin>>n;
    for(i=0;i<n;i++){
        cin>>a[i];
    }
    if(a[1]>a[0]){
        d=0;
    }else{
        d=1;
    }
    for(i=1;i<n;i++){
        if(d=0){
            if(a[i-1]>a[i]){
                d=1;
                s++;
            }
        }else{
            if(a[i-1]<a[i]){
                d=0;
                s++;
            }
        }
    }
    cout<<s;
    return 0;
}
/**************************************************************
	Problem: 1173
	User: lijinkai
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/