#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, ans = 0, c1 = 0, z = 0;
  cin >> n;
  long long int a[n];
  for (long long int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] < 0) {
      ans += (-1 - a[i]);
      c1++;
    } else if (a[i] == 0)
      z++;
    else
      ans += (a[i] - 1);
  }
  if (c1 % 2 && z)
    ans += z;
  else if (c1 % 2 && z == 0)
    ans += 2;
  else
    ans += z;
  cout << ans;
}
