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#include <iostream>
#include <bitset>
#include <vector>
#include <algorithm>
#include <cmath>

using namespace std;

void solve() {
	int n, ans1=0, ans2=0, next;
	cin >> n;
	vector<int> a(n+1), b(n);
	for (int i = 1; i <= n; i++)
		cin >> a[i];
	
	for (int i = 1; i < n; i++) {
		if (a[i+1] > a[i])
			b[i] = 1;
		if (a[i+1] < a[i])
			b[i] = -1;
		if (a[i+1] == a[i])
			b[i] = 0;
	}
	n--;
	
	next = -1;
	for (int i = 1; i <= n; i++) {
		if (b[i] == next) {
			next *= -1;
			continue;
		}
		i++;
		ans1++;
	}

	next = 1;
	for (int i = 1; i <= n; i++) {
		if (b[i] == next) {
			next *= -1;
			continue;
		}
		i++;
		ans2++;
	}

	cout << min(ans1, ans2);
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	
	solve();
	cout << '\n';

	return 0;
}