#include <bits/stdc++.h>
using namespace std;
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << "\n";
  err(++it, args...);
}
long long expo(long long x, long long n) {
  if (!n) return 1;
  if (n & 1)
    return (x * expo((x * x) % 1000000007, (n - 1) / 2)) % 1000000007;
  else
    return expo((x * x) % 1000000007, n / 2);
}
long long mod_inv(long long n) { return expo(n, 1000000007 - 2); }
inline long long add(long long a, long long b) {
  return ((a % 1000000007) + (b % 1000000007)) % 1000000007;
}
inline long long sub(long long a, long long b) {
  return ((a % 1000000007) - (b % 1000000007) + 1000000007) % 1000000007;
}
inline long long mul(long long a, long long b) {
  return ((a % 1000000007) * (b % 1000000007)) % 1000000007;
}
void speed_solve() {
  long long n;
  cin >> n;
  long long a[n], cost = 0;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] == 1 or a[i] == -1) {
      continue;
    }
    if (a[i] > 0) {
      cost += a[i] - 1;
      a[i] = 1;
    } else if (a[i] < 0) {
      cost += abs(a[i] + 1);
      a[i] = -1;
    }
  }
  long long c = 0, z = 0;
  for (long long i = 0; i < n; i++) {
    if (a[i] == -1) {
      c++;
    }
    if (a[i] == 0) {
      z++;
    }
  }
  cost += z;
  if (c & 1 and !z) {
    cost += 2;
  }
  cout << cost << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long tc = 1;
  for (long long i = 0; i < tc; i++) {
    speed_solve();
  }
  return 0;
}
