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// Witold Milewski
// Potyczki Algorytmiczne - 2022

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

int *oryginal;
int *sounds;
int *marks;

void fill_marks(int n, bool is_increase) {
  int x = 0;
  // czy zacząć od rosnącego
  if (is_increase) x = 1;
  int min_val = -1e6 - 1;
  int max_val = 1e6 + 1;

  for (int i = 1; i < n; i++) {
    if (x) {
      // ma się zwiększyć
      if (sounds[i] < sounds[i + 1])
        marks[i] = 0;
      else {
        marks[i] = 1;
        sounds[i + 1] = max_val;
        max_val++;
      }
    } else {
      // ma się zmniejszyć
      if (sounds[i] > sounds[i + 1])
        marks[i] = 0;
      else {
        marks[i] = 1;
        sounds[i + 1] = min_val;
        min_val--;
      }
    }

    if (x)
      x = 0;
    else if (!x)
      x = 1;
  }
}

int count(int n) {
  int res = 0;
  int x = 0;
  for (int i = 1; i <= n; i++) {
    if (marks[i] == 1)
      x++;
    else {
      res += ((x / 2) + (x % 2));
      x = 0;
    }
  }

  res += ((x / 2) + (x % 2));

  return res;
}

void set_sounds(int n) {
  for (int i = 1; i <= n; i++) {
    sounds[i] = oryginal[i];
  }
}

int main() {
  cin.tie(0);
  cout.tie(0);
  ios_base::sync_with_stdio(0);

  int n;
  cin >> n;

  // między i <-> i+1
  marks = new int[n + 7];
  oryginal = new int[n + 7];
  sounds = new int[n + 7];

  int x;
  for (int i = 1; i <= n; i++) {
    cin >> x;
    oryginal[i] = x;
  }

  set_sounds(n);
  fill_marks(n, true);
  int w1 = count(n - 1);

  set_sounds(n);
  fill_marks(n, false);
  int w2 = count(n - 1);

  int res = min(w1, w2);
  cout << res;
}