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// Olaf Surgut 12.12.2022 17:06:23
#include <bits/stdc++.h>

using namespace std;

const int N = 50000 + 11;

int n, a[N], dp[N][2][2]; // [i][dn|up][inf]

int main() {
	ios::sync_with_stdio(false), cin.tie(nullptr);
	
	cin >> n;
	for (int i = 1; i <= n; i++)
		cin >> a[i];
	
	for (int i = 1; i <= n; i++) {
		dp[i][0][0] = min(dp[i - 1][1][0] + (a[i - 1] <= a[i]),
						  dp[i - 1][1][1]);

		dp[i][0][1] = min(dp[i - 1][1][0], 
						  dp[i - 1][1][1]) + 1;
		
		dp[i][1][0] = min(dp[i - 1][0][0] + (a[i - 1] >= a[i]),
						  dp[i - 1][0][1]);
		
		dp[i][1][1] = min(dp[i - 1][0][0],
						  dp[i - 1][0][1]) + 1;
	}

	cout << min({dp[n][0][0], dp[n][0][1], dp[n][1][0], dp[n][1][1]}) << '\n';
}