#include <bits/stdc++.h>
using namespace std;
long long a[100001];
int main() {
  long long n, s1 = 0, s2 = 0, s3 = 0, pd = 0, ans;
  scanf("%lld", &n);
  for (int i = 1; i <= n; ++i) scanf("%lld", &a[i]);
  for (int i = 1; i <= n; ++i) {
    if (a[i] > 0) s1 += a[i] - 1;
    if (a[i] < 0) {
      s2 += abs(a[i]) - 1;
      pd++;
    }
    if (a[i] == 0) ++s3;
  }
  if (pd % 2 == 0 || s3 > 0)
    ans = s1 + s2 + s3;
  else
    ans = s1 + s2 + 2;
  printf("%lld\n", ans);
  return 0;
}
