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#include <bits/stdc++.h>
using namespace std;

const int INF = 1e9;

int solve(int n, vector<int> a, bool inc) {
    int last = a[0];
    int score = 0;

    for (int i = 1; i < n; i++) {
        if (inc) {
            if (a[i] > last) {
                last = a[i];
            }
            else {
                last = INF;
                score++;
            }
        }
        else {
            if (a[i] < last) {
                last = a[i];
            }
            else {
                last = -INF;
                score++;
            }
        }
        inc = !inc;
    }

    return score;
}

int main() {
    ios_base::sync_with_stdio(false);

    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    
    cout << min(solve(n, a, true), solve(n, a, false)) << endl;
}