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