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// B1 - Ornitolog
#include <iostream>
using namespace std;

#define MIN_VAL -1000000000
#define MAX_VAL  1000000000

int main() {
	ios_base::sync_with_stdio(0);
	int n, a, res1, res2, prev;
	int *notes;
	
	cin >> n;
	notes = new int[n];
	for (int i = 0; i < n; ++i) {
		cin >> a;		
		notes[i] = a;
	}
	
	res1 = 0;
	prev = MAX_VAL;
	for (int i = 0; i < n; ++i) {
		if (i % 2 == 0) {
			if (prev <= notes[i]) {
				++res1;
				prev = MIN_VAL;
			} else {
				prev = notes[i];
			}
		} else {
			if (prev >= notes[i]) {
				++res1;
				prev = MAX_VAL;
			} else {
				prev = notes[i];
			}
		}
	}
	
	res2 = 0;
	prev = MIN_VAL;
	for (int i = 0; i < n; ++i) {
		if (i % 2 == 0) {
			if (prev >= notes[i]) {
				++res2;
				prev = MAX_VAL;
			} else {
				prev = notes[i];
			}
		} else {
			if (prev <= notes[i]) {
				++res2;
				prev = MIN_VAL;
			} else {
				prev = notes[i];
			}
		}
	}
	
	cout << ((res1 < res2) ? res1 : res2) << endl;	
	
	delete [] notes;
	
	return 0;
}