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#include <iostream>

int64_t n;
int64_t a[50002];
int64_t p[50002][2];
int64_t inf = 1000000000;

int64_t find(bool high) {
    p[0][0] = 0;
    p[0][1] = 1;

    for (decltype(n) i = 1; i < n; i++, high = !high) {
        p[i][0] = p[i-1][1];
        if (high && a[i] > a[i-1]) {
            p[i][0] = std::min(p[i][0], p[i-1][0]);
        }
        if (!high && a[i] < a[i-1]) {
            p[i][0] = std::min(p[i][0], p[i-1][0]);
        }

        p[i][1] = std::min(p[i-1][0], p[i-1][1]) + 1;
    }

    return std::min(p[n-1][0], p[n-1][1]);
}

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

    std::cin >> n;
    for (decltype(n) i = 0; i < n; i++) {
        std::cin >> a[i];
    }

    std::cout << std::min(find(true), find(false)) << "\n";
}