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#include <vector>
#include <iostream>


int main() {
	int n;
	std::cin >> n;
	std::vector<int> v(n);
	for (int i = 0; i < n; i++)
		std::cin >> v[i];
	int corrections = 0;
	bool nextGoingUp = true;
	for (int i = 0; i < n - 1; i++) {
		if (v[i] > v[i + 1]) {
			if (nextGoingUp) {
				corrections++;
				i++;
			}
			else
				nextGoingUp = true;
		}
		else if (v[i] == v[i + 1]) {
			corrections++;
			i++;
		}
		else {
			if (nextGoingUp)
				nextGoingUp = false;
			else {
				corrections++;
				i++;
			}
		}
	}
	nextGoingUp = false;
	int temp = 0;
	for (int i = 0; i < n - 1; i++) {
		if (v[i] > v[i + 1]) {
			if (nextGoingUp) {
				temp++;
				i++;
			}
			else
				nextGoingUp = true;
		}
		else if (v[i] == v[i + 1]) {
			temp++;
			i++;
		}
		else {
			if (nextGoingUp)
				nextGoingUp = false;
			else {
				temp++;
				i++;
			}
		}
	}
	corrections = std::min(corrections, temp);
	std::cout << corrections;
}