#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, a, t = 0, x = 0, y = 0;
  cin >> n;
  while (n--) {
    cin >> a;
    if (a != 0) t += abs(a) - 1;
    if (a < 0) x++;
    if (a == 0) y++;
  }
  if (x % 2 == 1) {
    if (y == 0) {
      t += 2;
    } else {
      t += 1;
      y--;
    }
  }
  t += y;
  cout << t;
  return 0;
}
