#include <bits/stdc++.h>
using namespace std;
long long coin_count(long long n, long long arr[]) {
  long long flag = 0;
  long long count = 0;
  long long neg_count = 0;
  for (long long i = 0; i < n; i++) {
    if (arr[i] < 0) {
      count = count + abs(arr[i]) - 1;
      neg_count++;
    }
    if (arr[i] == 0) {
      count += 1;
      flag = 1;
    }
    if (arr[i] > 0) {
      count = count + (arr[i] - 1);
    }
  }
  if (neg_count % 2 == 0 || (neg_count % 2 != 0 && flag == 1))
    return count;
  else
    return count + 2;
}
int main() {
  long long n;
  cin >> n;
  long long *arr = new long long[n];
  for (long long i = 0; i < n; i++) {
    cin >> arr[i];
  }
  cout << coin_count(n, arr);
}
