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#include "bits/stdc++.h" // Tomasz Nowak
using namespace std;     // University of Warsaw
using LL = long long;
#define FOR(i, l, r) for(int i = (l); i <= (r); ++i)
#define REP(i, n) FOR(i, 0, (n) - 1)
#define ssize(x) int(x.size())
template<class A, class B> auto& operator<<(ostream &o, pair<A, B> p) {
	return o << '(' << p.first << ", " << p.second << ')';
}
template<class T> auto operator<<(ostream &o, T x) -> decltype(x.end(), o) {
	o << '{'; int i = 0; for(auto e : x) o << (", ")+2*!i++ << e; return o << '}';
}
#ifdef DEBUG
#define debug(x...) cerr << "[" #x "]: ", [](auto... $) {((cerr << $ << "; "), ...); }(x), cerr << '\n'
#else
#define debug(...) {}
#endif

int main() {
	cin.tie(0)->sync_with_stdio(0);

	int n;
	cin >> n;
	vector<int> a(n);
	for(int &ai : a)
		cin >> ai;

	int global_ans = n;
	REP(first_comparator, 2) {
		int local_ans = 0;
		int comparator = first_comparator;
		FOR(i, 1, n - 1) {
			auto f = (comparator ? function<bool (int, int)>(less<int>{}) : function<bool (int, int)>(greater<int>{}));
			if(f(a[i - 1], a[i])) {
				comparator ^= 1;
			}
			else {
				++local_ans;
				++i;
			}
		}
		debug(first_comparator, local_ans);
		global_ans = min(global_ans, local_ans);
	}
	cout << global_ans << '\n';
}