#include <bits/stdc++.h>
const long long INF32 = 1e9;
const long long INF64 = 1e17;
const int RANGE = 1e6 + 5;
using namespace std;
template <class T>
void read(T &Val) {
  T tmp = 0;
  char ch = getchar();
  int flag = 1;
  while (!(ch >= '0' && ch <= '9')) {
    if (ch == '-') flag = -1;
    ch = getchar();
  }
  while ((ch >= '0' && ch <= '9')) {
    tmp = tmp * 10 + ch - '0';
    ch = getchar();
  }
  Val = flag * tmp;
}
long long sum;
long long pos, neg, zer;
int main() {
  int n;
  read(n);
  for (int i = 0; i < n; i++) {
    int a;
    read(a);
    if (a == 1) pos++;
    if (a > 1) sum += (a - 1), pos++;
    if (a == 0) zer++;
    if (a == -1) neg++;
    if (a < -1) sum += (-a - 1), neg++;
  }
  if (zer == 0) {
    if (neg % 2 == 1) sum += 2;
  }
  if (zer != 0) {
    sum += zer;
  }
  cout << sum;
  return 0;
}
