#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  long long n, i;
  cin >> n;
  vector<long long> v;
  vector<long long>::iterator it;
  long long ar[n], neg = 0, ze = 0, cost = 0;
  for (i = 0; i < n; i++) {
    cin >> ar[i];
    if (ar[i] < 0) {
      v.push_back(ar[i]);
      neg++;
    } else if (ar[i] >= 1) {
      cost += ar[i] - 1;
    } else {
      ze++;
      cost++;
    }
  }
  if (neg % 2 == 0) {
    for (auto i : v) {
      cost += -1 - i;
    }
  } else {
    for (auto it = v.begin(); it != v.end(); it++) {
      *it = -*it;
    }
    sort(v.begin(), v.end());
    if (ze == 0) {
      for (auto it = v.begin(); it != v.end(); it++) {
        if (it == v.begin()) {
          cost += 1 + *it;
        } else {
          cost += *it - 1;
        }
      }
    } else {
      for (auto i : v) {
        cost += i - 1;
      }
    }
  }
  cout << cost;
  return 0;
}
