#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5 + 500;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const int LOG = 18;
const double EPS = 1e-9;
const double PI = 3.1415926535;
const int OFF = 1 << 17;
int main() {
  int n, a;
  int one = 0, min_one = 0, zero = 0;
  long long cost = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a;
    if (a < 0) {
      min_one++;
      cost += -(a + 1);
    } else if (a > 0) {
      one++;
      cost += (a - 1);
    } else {
      zero++;
      cost += 1;
    }
  }
  if (min_one % 2 != 0) {
    if (zero != 0)
      cout << cost << endl;
    else
      cout << cost + 2 << endl;
  } else {
    cout << cost << endl;
  }
  return 0;
}
