#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 500;
const long long mod = 1e9 + 7;
const long long INF = 1LL << 57;
const int M = 1e6 + 500;
void solve() {
  long long int n;
  cin >> n;
  long long int a[n];
  long long int p = 1;
  long long int ans = 0;
  long long int cnt = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    ans += abs(abs(a[i]) - 1);
    if (a[i] == 0) cnt++;
    if (a[i] >= 0)
      a[i] = 1;
    else
      a[i] = -1;
    p *= a[i];
  }
  if (p == -1 && cnt == 0) {
    ans += 2;
  }
  cout << ans;
  return;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int t;
  t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
