#include <bits/stdc++.h>
using namespace std;
void _print(char n) { cerr << n; }
void _print(int n) { cerr << n; }
void _print(bool n) { cerr << n; }
void _print(string n) { cerr << n; }
void _print(long long n) { cerr << n; }
void _print(double n) { cerr << n; }
template <class T>
void _print(vector<T> v) {
  cerr << "[ ";
  for (T i : v) {
    _print(i);
    cerr << " ";
  }
  cerr << "]";
}
template <class T>
void _print(set<T> v) {
  cerr << "[ ";
  for (T i : v) {
    _print(i);
    cerr << " ";
  }
  cerr << "]";
}
template <class T, class V>
void _print(map<T, V> v) {
  cerr << "[ ";
  for (auto i : v) {
    cerr << "(";
    _print(i.ff);
    cerr << ",";
    _print(i.ss);
    cerr << ")";
    cerr << " ";
  }
  cerr << "]";
}
const int N = 1e7 + 7;
vector<int> prime(N);
void seive() {
  for (int i = 2; i < N; i++) {
    if (prime[i] == 0) {
      int j = 2;
      while (i * j <= N) {
        prime[i * j] = 1;
        j++;
      }
    }
  }
}
void no() {
  cout << "-1"
       << "\n";
}
bool cmp(pair<string, int> a, pair<string, int> b) {
  return a.second > b.second ? true : false;
}
void solve() {
  int n;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
  vector<int> pos;
  vector<int> neg;
  vector<int> zero;
  for (int i = 0; i < n; i++) {
    if (v[i] > 0) pos.push_back(v[i]);
    if (v[i] < 0) neg.push_back(v[i]);
    if (v[i] == 0) zero.push_back(v[i]);
  }
  long long int cost = 0;
  if (neg.size() % 2 == 0) {
    for (int i = 0; i < n; i++) {
      if (v[i] < 0 && v[i] != -1) {
        cost = cost + (-1 - v[i]);
      }
      if (v[i] == 0) {
        cost = cost + 1;
      }
      if (v[i] > 0 && v[i] != 1) {
        cost += (v[i] - 1);
      }
    }
    cout << cost << "\n";
    return;
  }
  if (neg.size() % 2 == 1) {
    if (zero.size() != 0) {
      for (int i = 0; i < n; i++) {
        if (v[i] < 0 && v[i] != -1) {
          cost = cost + (-1 - v[i]);
        }
        if (v[i] == 0) {
          cost = cost + 1;
        }
        if (v[i] > 0 && v[i] != 1) {
          cost += (v[i] - 1);
        }
      }
      cout << cost << "\n";
      return;
    } else {
      for (int i = 0; i < n; i++) {
        if (v[i] < 0 && v[i] != -1) {
          cost = cost + (-1 - v[i]);
        }
        if (v[i] == 0) {
          cost = cost + 1;
        }
        if (v[i] > 0 && v[i] != 1) {
          cost += (v[i] - 1);
        }
      }
      cout << cost + 2 << "\n";
      return;
    }
  }
}
int main() {
  cin.tie(NULL);
  cout.tie(NULL);
  ios_base::sync_with_stdio(false);
  int t;
  t = 1;
  while (t--) {
    solve();
  }
}
