#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int a, p, q, l, b = 0, i, d, m, n, k, sum = 0, t = 1, x = 0, z = 0,
                            y = 0;
  vector<long long int> v;
  cin >> a;
  for (int i = 0; i < a; i++) {
    cin >> x;
    if (x > 0) {
      sum = sum + (x - 1);
    } else if (x == 0) {
      y++;
    } else {
      p = -x - 1;
      sum = sum + p;
      z++;
    }
  }
  sum = sum + y;
  if (z % 2 == 1 && y == 0) {
    sum = sum + 2;
  }
  cout << sum;
  return 0;
}
