#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  long long ans = 0;
  cin >> n;
  vector<int> s1, s2;
  for (int i = 1; i <= n; i++) {
    int x;
    cin >> x;
    if (abs(x - 1) <= abs(x + 1))
      ans += abs(x - 1), s1.push_back(x);
    else
      ans += abs(x + 1), s2.push_back(x);
  }
  if (s2.size() % 2 == 0)
    cout << ans;
  else {
    long long t1 = 1e18, t2 = 1e18;
    for (int x : s1) t1 = min(t1, ans - abs(x - 1) + abs(x + 1));
    for (int x : s2) t2 = min(t2, ans - abs(x + 1) + abs(x - 1));
    ans = min(t1, t2);
    cout << ans;
  }
  return 0;
}
