#include <iostream>
#include <vector>
#include <algorithm>
#define int long long
using namespace std;


vector<int> stars;

int binary(int f, int t, int value)
{
    if (f > t)
    {
        return -1;
    }
    int mid = (f + t)/2;
    if(stars[mid] == value)
    {
        return mid;
    }
    if(stars[mid] < value)
    {
        return binary(mid + 1, t, value);
    }
    else
    {
        return binary(f, mid - 1, value);
    }
}

signed main()
{
    ios_base::sync_with_stdio(0);
    int counta;
    cin >> counta;
    for(int i =0 ; i < counta; ++i)
    {
        int x, y;
        cin >> x >> y;
        x += 1000;
        y += 1000;
        stars.push_back(3000 * x + y);
    }
    sort(stars.begin(), stars.end());
    int result = 0;
    for(int i = 1; i < counta; ++i)
    {
        int dif = stars[i] - stars[0];
        bool correct = true;
        for(int j = 0; j < counta; ++j)
        {
            int index = binary(0, counta - 1, stars[j] + dif);
            if(index == -1)
            {
                index = binary(0, counta - 1, stars[j] - dif);
            }
            if(index == -1)
            {
                correct = false;
                break;
            }
        }
        if(correct)
        {
            result += 2;
        }
    }

    cout << result << endl;
    return 0;
}