#include <bits/stdc++.h>
using namespace std;
vector<int> prime_Numbers;
bool primes[1000005];
void prime(int n) {
  for (int i = 2; i <= n; i++) primes[i] = true;
  for (int i = 2; i <= n; i++) {
    if (primes[i] == true) {
      prime_Numbers.push_back(i);
      for (int j = i + i; j <= n; j += i) primes[j] = false;
    }
  }
}
int fib(int n) {
  if (n == 1 || n == 0) return n;
  return fib(n - 1) + fib(n - 2);
}
long long fastpower(int b, int p) {
  if (p == 0) return 1;
  long long term = fastpower(b, p / 2);
  term *= term;
  if (p % 2 != 0) return term *= b;
  return term;
}
int main() {
  long long n, sum = 1, cntr = 0, zeros = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    long long x;
    cin >> x;
    if (x <= -1) {
      cntr += abs(x) - 1;
      x = -1;
    } else if (x >= 1) {
      cntr += abs(x - 1);
      x = 1;
    } else if (x == 0) {
      zeros++;
    }
    sum *= x;
  }
  if (sum == -1 && zeros == 0)
    cout << cntr + 2;
  else if (sum == -1 && zeros > 0)
    cout << cntr + zeros;
  else
    cout << cntr + zeros;
  return 0;
}
