#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, i, j = 0, l = 0, sum = 0;
  cin >> n;
  long long int a[n];
  for (i = 0; i < n; i++) cin >> a[i];
  for (i = 0; i < n; i++) {
    if (abs(a[i]) != 1) sum = sum + abs(abs(a[i]) - 1);
    if (a[i] < 0) l++;
    if (a[i] == 0) j = 1;
  }
  if (l % 2 != 0 && j == 0) sum = sum + 2;
  cout << sum << endl;
  return 0;
}
