#include <bits/stdc++.h>
using namespace std;
int main() {
  long long sum = 0, sum1 = 0, cnt = 0, cnt1 = 0;
  int n;
  cin >> n;
  long long ara[100006];
  for (int i = 0; i < n; i++) {
    cin >> ara[i];
  }
  for (int i = 0; i < n; i++) {
    if (ara[i] < 0) {
      sum += abs(ara[i] - (-1));
      cnt++;
    }
    if (ara[i] > 0) {
      sum1 += ara[i] - 1;
    }
    if (ara[i] == 0) cnt1++;
  }
  if (cnt % 2 == 0)
    cout << sum + sum1 + cnt1 << endl;
  else if (cnt % 2 == 1 && cnt1 > 0)
    cout << sum + sum1 + cnt1 << endl;
  else if (cnt % 2 == 1)
    cout << sum + sum1 + cnt1 + 2 << endl;
  return 0;
}
