#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  long long a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  long long ans = 0;
  long long k = 0;
  long long cp = 0, cn = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] > 0)
      ans += a[i] - 1, cp++;
    else if (a[i] < 0)
      ans += -1 - a[i], cn++;
    else
      k++;
  }
  if (k > 0)
    ans += k;
  else if (k == 0 && cn % 2 != 0)
    ans += 2;
  cout << ans;
}
