#include <bits/stdc++.h>
using namespace std;
int main() {
  int negativos = 0;
  int zeros = 0;
  long long sums = 0;
  int qtd;
  int number;
  cin >> qtd;
  while (qtd--) {
    cin >> number;
    if (number <= -1) {
      sums += -1 - number;
      negativos++;
    } else if (number >= 1) {
      sums += number - 1;
    } else if (number == 0) {
      sums++;
      zeros++;
    }
  }
  if (negativos % 2 == 1) {
    if (!zeros) {
      sums += 2;
    }
  }
  cout << sums << "\n";
}
