#include <bits/stdc++.h>
using namespace std;
long long n, ans, neg, tmp, mn = 1e18;
vector<long long> a, b;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  a.resize(n);
  for (auto &x : a) {
    cin >> x;
  }
  b = a;
  for (auto &x : a) {
    if (abs(x - (-1)) < abs(x - 1)) {
      ans += abs(x - (-1));
      x = -1;
      ++neg;
    } else {
      ans += abs(x - 1);
      x = 1;
    }
  }
  if (neg % 2 == 0) {
    cout << ans << "\n";
    return 0;
  }
  for (int i = 0; i < b.size(); ++i) {
    tmp = ans - abs(b[i] - a[i]);
    if (a[i] != -1) {
      mn = min(mn, abs(b[i] - (-1)) + tmp);
    } else {
      mn = min(mn, abs(b[i] - 1) + tmp);
    }
  }
  cout << mn << "\n";
  return 0;
}
