#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
int main() {
  ll n;
  cin >> n;
  ll ar[n];
  ll neg = 0, z = 0, ans = 0;
  for (ll i = 0; i < n; i++) {
    int a;
    cin >> a;
    if (a < 0) {
      ans += ((-a) - 1);
      neg++;
    } else if (a == 0) {
      ans++;
      z++;
    } else
      ans += a - 1;
  }
  if (neg % 2 == 0)
    cout << ans << endl;
  else if (z > 0)
    cout << ans << endl;
  else
    cout << ans + 2 << endl;
  return 0;
}
