#include <bits/stdc++.h>
using namespace std;
bool is_prime(int n) {
  bool prime[n + 1];
  memset(prime, true, sizeof(prime));
  for (int p = 2; p * p <= n; p++) {
    if (prime[p]) {
      for (int i = p * p; i <= n; i += p) prime[i] = false;
    }
  }
  return prime[n];
}
long long int bsearch(vector<long long int> v, long long int k) {
  long long int lo = 0, hi = v.size() - 1;
  long long int mid = (lo + hi) / 2;
  while (lo <= hi) {
    mid = (lo + hi) / 2;
    if (k > v[mid])
      lo = mid + 1;
    else if (k < v[mid])
      hi = mid - 1;
    else
      return mid;
  }
}
void solve() {
  long long int n;
  cin >> n;
  long long int a[n];
  long long int z = 0, t = 0;
  for (long long int i = 0; i <= n - 1; i++) {
    cin >> a[i];
    if (a[i] == 0)
      z++;
    else if (a[i] > 0) {
      t += a[i] - 1;
      a[i] = 1;
    } else {
      t += -1 - a[i];
      a[i] = -1;
    }
  }
  long long int p = 1;
  for (long long int i = 0; i <= n - 1; i++) {
    if (a[i] != 0) p *= a[i];
  }
  if (p == 1)
    t += z;
  else {
    if (z == 0)
      t += 2;
    else
      t += z;
  }
  cout << t;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int t = 1;
  while (t--) solve();
}
