#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  long long int n, m = 0, p = 0, cnt = 0, f = 0;
  cin >> n;
  long long int a[n];
  for (long long int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] < 0) {
      m++;
    }
    if (a[i] > 0) p++;
    if (a[i] < 0) {
      cnt = cnt - a[i] - 1;
    }
    if (a[i] > 0) {
      cnt = cnt + a[i] - 1;
    }
    if (a[i] == 0) {
      cnt = cnt + 1;
      f++;
    }
  }
  if (f and m % 2 == 0) cout << cnt << endl;
  if (f and m % 2 != 0) cout << cnt << endl;
  if (!f and m % 2 == 0) cout << cnt << endl;
  if (!f and m % 2 != 0) cout << cnt + 2 << endl;
}
