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#include <bits/stdc++.h>
using namespace std;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 LOG(x...)cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...)<<'\n';}(x)
#else
#define LOG(x...)
#endif

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	int size;
	cin >> size;

	vector<int> values(size);

	for (auto &value : values)
		cin >> value;

	int result = INT_MAX;

	for (bool state_up : { false, true }) {
		bool current_state_up = state_up;
		int previous = state_up ? (int)-1e9 : (int)1e9;
		int current_result = 0;

		for (int index = 0; index < size; index++) {
			if (current_state_up) {
				if (previous >= values[index]) {
					previous = (int)1e9;
					current_result++;
				} else {
					previous = values[index];
				}
			} else {
				if (previous <= values[index]) {
					previous = (int)-1e9;
					current_result++;
				} else {
					previous = values[index];
				}
			}

			current_state_up = !current_state_up;
		}

		result = min(result, current_result);
	}

	cout << result << '\n';
}