#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cout.tie(0);
  cin.tie(0);
  int n;
  cin >> n;
  long long ans = 0, neg = 0, zer = 0;
  for (int i = 0; i < n; ++i) {
    int tmp;
    cin >> tmp;
    if (tmp == 0) zer++;
    if (tmp < 0) neg ^= 1;
    ans += abs(abs(tmp) - 1);
  }
  if (neg && !zer)
    cout << ans + 2;
  else
    cout << ans;
}
