#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 1e3;
int t, p, n, l[N], z;
long long c;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> t;
  for (int i = 0; i < t; ++i) {
    cin >> l[i];
    c += abs(l[i]) - 1;
    if (l[i] > 0)
      p++;
    else if (l[i] < 0)
      n++;
    else
      z++;
  }
  if (n % 2 && !z) c += 2;
  c += z * 2;
  cout << c;
}
