#include <cstdio>
#include <algorithm>
#include <vector>
#include <cmath>

#define base 666013
#define pii pair <int, int>
#define f first
#define s second

using namespace std;

vector <int> has[base];
pii v[1024];

inline int mod (int val)
{
    val %= base;
    val += base;
    val %= base;

    return val;
}

inline bool fin (pii x)
{
    pii y = x;
    y.f *= base;
    y.f += y.s;
    int ind = mod (y.f);

    for (auto &it : has[ind])
        if (v[it] == x) return true;

    return false;
}

inline int aprox (double val)
{
    int x = floor (val);
    int y = ceil (val);

    double xx = 1.0 * x;
    double yy = 1.0 * y;

    if (val - xx < yy - val) return x;
    return y;
}

int main ()
{
    freopen ("patrate3.in", "r", stdin);
    freopen ("patrate3.out", "w", stdout);

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

    for (int i = 1; i <= n; ++i)
    {
        double xx, yy;
        scanf ("%lf %lf", &xx, &yy);

        xx *= 10000.0;
        yy *= 10000.0;

        int x = aprox(xx);
        int y = aprox(yy);

        v[i] = pii (x, y);
        x *= base;
        x += y;

        has[mod(x)].push_back (i);
    }

    int rez = 0;
    for (int i = 1; i <= n; ++i)
        for (int j = i + 1; j <= n; ++j)
        {
            int m1 = (v[i].f + v[j].f) >> 1;
            int m2 = (v[i].s + v[j].s) >> 1;

            if ((v[i].f + v[j].f) % 2 || (v[i].s + v[j].s) % 2) continue;

            int d1 = m1 - v[i].f;
            int d2 = m2 - v[i].s;

            pii x = {m1 - d2, m2 + d1};
            pii y = {m1 + d2, m2 - d1};

            if (fin (x) && fin (y)) ++rez;
        }

    printf ("%d\n", rez >> 1);

    return 0;
}