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#include <bits/stdc++.h>
using namespace std;
int main() {
	// freopen("in.txt", "r", stdin);
	ios::sync_with_stdio(false), cin.tie(0);
	int n;
	cin >> n;
	vector<int> a(n);
	auto solve = [&] (vector<int> &a) {
		vector<array<int, 2>> dp(n);
		dp[0][0] = 1, dp[0][1] = 0;
		for(int i = 1; i < n; i ++) {
			if(i & 1) {
				dp[i][1] = dp[i - 1][0];
				if(a[i] > a[i - 1]) dp[i][1] = min(dp[i][1], dp[i - 1][1]);
				dp[i][0] = min(dp[i - 1][0], dp[i - 1][1]) + 1;
			} else {
				dp[i][1] = dp[i - 1][0];
				if(a[i] < a[i - 1]) dp[i][1] = min(dp[i][1], dp[i - 1][1]);
				dp[i][0] = min(dp[i - 1][0], dp[i - 1][1]) + 1;
			}
		}
		return min(dp.back()[0], dp.back()[1]);
	};
	for(int &u : a) cin >> u;
	int ans = solve(a);
	for(int &u : a) u *= -1;
	cout << min(solve(a), ans) << '\n';
	return 0;
}