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#include <bits/stdc++.h>
#ifdef LOC
#include "debuglib.h"
#else
#define deb(...)
#define DBP(...)
#endif
using namespace std;
using   ll         = long long;
using   vi         = vector<int>;
using   pii        = pair<int, int>;
#define pb           push_back
#define mp           make_pair
#define x            first
#define y            second
#define rep(i, b, e) for (int i = (b); i < (e); i++)
#define each(a, x)   for (auto& a : (x))
#define all(x)       (x).begin(), (x).end()
#define sz(x)        int((x).size())

void run() {
	int n; cin >> n;
	vi elems(n);
	each(e, elems) cin >> e;
	int ans = INT_MAX;
	for (int flip : {1, -1}) {
		int alt = 0;
		rep(i, 1, n) {
			int cmp = (elems[i-1] - elems[i]) * flip;
			if (i%2) cmp *= -1;
			if (cmp <= 0) {
				alt++;
				i++;
			}
		}
		ans = min(ans, alt);
	}
	cout << ans << '\n';
}

int main() {
	cin.sync_with_stdio(0); cin.tie(0);
	cout << fixed << setprecision(10);
	run();
	cout << flush; _Exit(0);
}