#include <bits/stdc++.h>
using namespace std;
const long long DIM = 100007;
const long long INF = 1000000007;
long long n, m, k;
long long a, b, c, d;
long long v[DIM];
long long v1[DIM];
long long ans;
string s;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  long long neg = 0;
  long long nul = 0;
  for (long long i = 1; i <= n; i++) {
    cin >> v[i];
    if (v[i] == 0) {
      ans++;
      nul = 1;
    } else if (v[i] < 0) {
      ans += (v[i] * -1) - 1;
      neg++;
    } else if (v[i] > 0)
      ans += v[i] - 1;
  }
  if (neg % 2 && nul == 0) ans += 2;
  cout << ans;
  return 0;
}
