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#include <iostream>
#include <vector>
using namespace std;

int MAX = 100000000;

inline int sgn(int x)
{
    return (x > 0) ? 1 : (x == 0 ? 0 : -1);
}

int uporzadkuj(int delta, int A[], int n)
// jesli delta = +1, to oczekujemy, ze dwa elementy sa w porzadku rosnacym: A[i] < A[i+1]
// jesli delta = -1, to oczekujemy, ze dwa elementy sa w porzadku malejacym: A[i] > A[i+1]
{
    int lzmian = 0;
    //    cout << "przebieg " << delta << endl;
    for (int i = 1; i < n; i++)
    {
        if (sgn(A[i] - A[i - 1]) != delta)
        {
            ++lzmian;
            // cout << delta << " --- " << i << ": A[i] = " << A[i] << ", A[i-1] = " << A[i - 1] << endl;
            A[i] = delta * MAX;
        }
        delta = -delta;
    }
    return lzmian;
}

int main()
{
    int n;
    scanf("%d", &n);
    int A[n], B[n];
    int el;

    // wczytaj ciag
    for (int i = 0; i < n; i++)
    {
        scanf("%d", &el);
        A[i] = el;
        B[i] = el;
    }

    int k1 = uporzadkuj(1, A, n);
    int k2 = uporzadkuj(-1, B, n);

    printf("%d\n", min(k1, k2));

    return 0;
}