#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long n, i, j, k, temp, x, y, t, h, o = 0, m = 0, z = 0;
  vector<long long> a;
  cin >> n;
  long long cost = 0;
  for (i = 0; i < n; i++) {
    cin >> t;
    if (t > 0)
      cost += t - 1, o++;
    else if (t < 0)
      cost += abs(-t - 1), m++;
    else
      z++, cost++;
  }
  if (z == 0 && m % 2 == 1) cost += 2;
  cout << cost << endl;
  return 0;
}
