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#include <iostream>
#include <vector>
using namespace std;
int main() {
  int n;
  cin >> n;
  int dp[2] = {0, 0};
  int prev[2] = {(int)-1e9, (int)1e9};
  bool inc[2] = {true, false};
  for (int i = 1, x; i <= n; i++, swap(inc[0], inc[1])) {
    cin >> x;
    for (int j = 0; j < 2; j++) {
      if (inc[j] && prev[j] >= x) {
        dp[j]++;
        prev[j] = 1e9;
      } else if (!inc[j] && prev[j] <= x) {
        dp[j]++;
        prev[j] = -1e9;
      } else {
        prev[j] = x;
      }
    }
  }
  cout << min(dp[0], dp[1]) << '\n';
}