#include <bits/stdc++.h>
using namespace std;
using namespace std;
int arr[100009];
int main() {
  long long int n, z = 0, nn = 0, neg = 0, pp = 0, pos = 0, sum = 0, tt = 0;
  cin >> n;
  for (int i = int(0); i <= int(n - 1); i++) {
    cin >> arr[i];
    if (arr[i] < 0) {
      neg += arr[i];
      nn++;
    } else if (arr[i] > 0) {
      pos += arr[i];
      pp++;
    } else
      z++;
  }
  sum += z;
  sum += (pos - pp);
  sum += (llabs(neg) - nn);
  if (!(nn & 1)) {
    cout << sum << endl;
    return 0;
  }
  if (z > 0) {
    cout << sum << endl;
    return 0;
  }
  sum += 2;
  cout << sum << endl;
  return 0;
}
