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#include <iostream>
#include <vector>

using namespace std;

vector<int> list;
vector<int> list2;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;

  int a = 0;
  int b = 0;
  int t;
  for (int i = 0; i < n; i++) {
    cin >> t;
    list.push_back(t);
  }

  for (int i = 1; i < n; i++) {
    if ((list[i] > list[i - 1]))
      list2.push_back(0);
    else if ((list[i] < list[i - 1]))
      list2.push_back(1);
    else if ((list[i] == list[i - 1]))
      list2.push_back(2);
  }

  for (int i = 0; i < n - 1; i++) {
    if (list2[i] != (i % 2) || list2[i] == 2) {
      a++;
      i++;
    }
  }

  for (int i = 0; i < n - 1; i++) {

    if (list2[i] == (i % 2) || list2[i] == 2) {
      b++;
      i++;
    }
  }

  cout << ((a < b) ? a : b);
}