#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1e9 + 7;
int main() {
  long long int t, n, ans = 0, count0 = 0, count1 = 0, count2 = 0, num0 = 0,
                      num1 = 0, num2 = 0;
  t = 1;
  while (t--) {
    cin >> n;
    vector<long long int> A(n, 0);
    for (int i = 0; i < n; i++) {
      cin >> A[i];
    }
    sort(A.begin(), A.end());
    for (int i = n - 1; i >= 0; i--) {
      if (A[i] > 0) {
        count1 += (A[i] - 1);
        num1++;
      } else if (A[i] == 0) {
        count0++;
        num0++;
      } else {
        count2 += (-1 - A[i]);
        num2++;
      }
    }
    ans += count1;
    if (num2 % 2 == 0) {
      ans += count2;
      ans += count0;
    } else {
      if (num0 > 0) {
        ans += count0;
        ans += count2;
      } else {
        ans += count0;
        ans += (count2 + 2);
      }
    }
    cout << ans << endl;
  }
  return 0;
}
