#include <bits/stdc++.h>

struct pi
{
    int x;
    int y;
    pi minus()
    {
        pi result;
        result.x = this->x;
        result.y = this->y;
        return result;
    }
};
struct picomparator
{
    bool operator() (const pi& a, const pi& b)
    {
        if(a.x < b.x)
            return true;
        else if(a.x > b.x)
            return false;
        else
            return a.y < b.y;
    }
};

pi piminus(const pi& v1, const pi& v2)
{
    pi result;
    result.x = v1.x - v2.x;
    result.y = v1.y - v2.y;
    return result;
}

int main()
{
    pi stars[1010];
    int totalVectors = 0;

    int starCount;
    scanf("%d", &starCount);

    for(int i = 0; i < starCount; i++)
    {
        scanf("%d%d", &stars[i].x, &stars[i].y);
    }

    std::set<pi, picomparator> differences[1010];
    for(int i = 0; i < starCount; i++)
    {
        for(int j = 0; j < starCount; j++)
        {
            if(i != j)
                differences[i].insert(piminus(stars[i], stars[j]));
        }
    }

    std::set<pi, picomparator> possibleDiffVectors;
    for(int i = 0; i < starCount; i++)
    {
        possibleDiffVectors.insert(differences[i].begin(), differences[i].end());
    }

    for(auto it = possibleDiffVectors.begin(); it != possibleDiffVectors.end(); it++)
    {
        const pi curr = *it;

        int i;
        for(i = 0; i < starCount; i++)
        {
            if(differences[i].find(curr) == differences[i].end() && differences[i].find(curr.minus()) == differences[i].end())
                break;
        }
        if(i == starCount)
            totalVectors++;
    }

    printf("%d", totalVectors);




    return 0;
}