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