#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
using namespace std;
const int N = 55;

struct Ant{
    int pos;
    bool isCold;

    bool operator < (const Ant& a) const {
        return abs(pos) < abs(a.pos);
    }
}ants[N];

int main()
{
    int n;
    scanf("%d", &n);
    ants[0].isCold = true;
    for (int i = 0; i < n; ++i) scanf("%d", &ants[i].pos);
    sort(ants, ants+n);
    int l = 0, r = n-1, res = 0;
    while (l <= r)
    {
        while (l <= r && ants[l].pos < 0) 
        {
            if (ants[l].isCold) res++;
            l++;
        }
        while (l <= r && ants[r].pos > 0) 
        {
            if(ants[r].isCold) res++;
            r--;
        }
        for (int i = l; i < r; ++i)
        {
            if (ants[i].pos * ants[i+1].pos < 0)
            {
                ants[i].isCold = ants[i+1].isCold = ants[i].isCold | ants[i+1].isCold;
                ants[i].pos *= -1;
                ants[i+1].pos *= -1;
            }
        }
    }
    printf("%d", res);
    return 0;
}