#include <iostream>

using namespace std;

int a[100100];

int main(){
    int n, m, k, knul;
    m = 0;
    k = 0;
    knul = 0;
    cin >> n;
    for (int i = 0; i < n; ++i){
        cin >> a[i];
        if  (a[i] > 1){
            while (a[i] != 1){
                m += 1;
                a[i] -= 1;
            }
        }
        if (a[i] <= -1){
            while (a[i] != -1){
                m +=1;
                a[i] +=1;
            }
        k+=1;
        }
        if (a[i] == 0){
            knul+=1;
        }
    }
    if (k > 0 && knul > 0 && k%2!=0){
        m+=1;
        k+=1;
        knul-=1;
    }
    if (k > 0 && knul == 0 && k%2 != 0){
        m+=2;
        k-=1;
    }
    m += knul;
    cout << m << endl;
    return 0;
}