#include <bits/stdc++.h>
using namespace std;
bool isPrime(int n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (int i = 5; i * i <= n; i = i + 6)
    if (n % i == 0 || n % (i + 2) == 0) return false;
  return true;
}
int nextPrime(int N) {
  if (N <= 1) return 2;
  int prime = N;
  bool found = false;
  while (!found) {
    prime++;
    if (isPrime(prime)) found = true;
  }
  return prime;
}
long long int powerexp(long long int x, long long int n) {
  long long int result = 1;
  while (n) {
    if (n & 1) result = result * x % 1000000007;
    n = n / 2;
    x = x * x % 1000000007;
  }
  return result;
}
int gcd(int a, int b) {
  if (a == 0) return b;
  if (b == 0) return a;
  if (a == b) return a;
  if (a > b) return gcd(a - b, b);
  return gcd(a, b - a);
}
int largest_divisor(long long int n) {
  long long int i;
  for (i = n / 2; i >= 1; i--) {
    if (n % i == 0) {
      return i;
    }
  }
  return 0;
}
bool checkPalindrome(string str) {
  int n = str.length();
  int count = 0;
  for (int i = 0; i < n / 2; ++i)
    if (str[i] != str[n - i - 1]) ++count;
  return (count <= 1);
}
bool countDivisors(long long int n) {
  int cnt = 0;
  for (int i = 3; i <= sqrt(n); i = i + 2) {
    if (n % i == 0) {
      return true;
    }
  }
  return false;
}
long long int factorial(long long int n) {
  if (n == 0) return 0;
  return n * factorial(n - 1);
}
long long int lcm(long long int a, long long int b) {
  return (a / gcd(a, b)) * b;
}
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
}
int main() {
  long long int t = 1;
  while (t--) {
    long long int n;
    cin >> n;
    long long int a[n];
    long long int z = 0, p = 0, neg = 0;
    long long int res = 0;
    for (long long int i = 0; i < n; i++) {
      cin >> a[i];
      if (a[i] == 0) {
        res++;
        z++;
      } else if (a[i] > 0) {
        res = res + (a[i] - 1);
        p++;
      } else {
        res = res + (-1 - a[i]);
        neg++;
      }
    }
    if (neg % 2 == 1 && z == 0) {
      res += 2;
    }
    cout << res << endl;
  }
  return 0;
}
