#include <bits/stdc++.h>
using namespace std;
long long a[100005];
int main() {
  int n;
  long long sum = 0, res = 1, c = 0;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    long long x;
    scanf("%lld", &x);
    if (x < 0)
      sum += -1 - x, res *= -1;
    else if (x == 0)
      sum++, c++;
    else
      sum += x - 1;
  }
  if (c > 0 || res == 1)
    printf("%lld\n", sum);
  else
    printf("%lld", sum + 2);
  return 0;
}
