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#include <iostream>

using namespace std;

int maximum_size = 50000;
int min_variable = -1000001;
int max_variable = 1000001;

int Smaller_bigger(int size, int arr[]){
    int low = 1, high = 1, org = 0;
    
    for (int i = 1; i < size; i++){
        int low2 = maximum_size, high2 = maximum_size, org2 = maximum_size;
        if(i % 2 == 0) {
          low2 = min(org + 1, high + 1);
          org2 = high;
          if (arr[i] < arr[i - 1]) org2 = min(org2, org);
        }
        else if (i % 2 == 1){
          high2 = min(org + 1, low + 1);
          org2 = low;
          if (arr[i] > arr[i - 1]) org2 = min(org2, org);
        }
        low = low2; high = high2; org = org2;
    }
    return min(low, min(high, org));
}

int Bigger_smaller(int size, int arr[]){
    int low = 1, high = 1, org = 0;
    
    for (int i = 1; i < size; i++){
        int low2 = maximum_size, high2 = maximum_size, org2 = maximum_size;
        if(i % 2 == 1) {
          low2 = min(org + 1, high + 1);
          org2 = high;
          if (arr[i] < arr[i - 1]) org2 = min(org2, org);
        }
        else if (i % 2 == 0){
          high2 = min(org + 1, low + 1);
          org2 = low;
          if (arr[i] > arr[i - 1]) org2 = min(org2, org);
        }
        low = low2; high = high2; org = org2;
    }
    return min(low, min(high, org));
}

int main()
{
    int n;
    int arr[maximum_size];
    cin >> n;
    for (int i = 0; i < n; i++){
        cin >> arr[i];
    }
    int first_check = Smaller_bigger(n, arr);
    int second_check = Bigger_smaller(n, arr);
    int result = (first_check < second_check) ? first_check : second_check;
    cout << result << endl;
    return 0;
}