#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <assert.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;


#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
const int maxn = 10007 + 20;
struct node {
    int x, y;
    bool operator < (const struct node & rhs) const {
        if (x != rhs.x) {
            return x < rhs.x;
        } else return y < rhs.y;
    }
    bool operator != (const struct node & rhs) const {
        return !(x == rhs.x && y == rhs.y);
    }
} arr[2222];
int n;
const int MOD = 10007;
struct Edge {
    int val, id, tonext;
}e[maxn * 2];
int first[maxn];
int num;
void add(int val, int id) {
    ++num;
    int tval = val;
    val %= MOD;
    e[num].id = id;
    e[num].val = tval;
    e[num].tonext = first[val];
    first[val] = num;
}
bool tofind(int val, int one, int two) {
    assert(val >= 0);
    int tval = val;
    val %= MOD;
    for (int i = first[val]; i; i = e[i].tonext) {
        if (e[i].val == tval && e[i].id != one && e[i].id != two) return true;
    }
    return false;
}
bool check(struct node t1, struct node t2, int one, int two) {
    return tofind(t1.x * 20001 + t1.y, one, two) &&
           tofind(t2.x * 20001 + t2.y, one, two);
}
void work() {
//    cout << (20000 + 20000) * 20001 << endl;
    num = 0;
    memset(first, 0, sizeof first);
    for (int i = 1; i <= n; ++i) {
        scanf("%d%d", &arr[i].x, &arr[i].y);
        arr[i].x += 40020;
        arr[i].y += 40020;
        add(arr[i].x * 20001 + arr[i].y, i);
        assert(arr[i].x * 20001 + arr[i].y >= 0);
    }
//    cout << tofind(arr[1].x * 20001 + arr[1].y, 3, 2) << endl;
//    sort(arr + 1, arr + 1 + n);
//    for (int i = 1; i <= n; ++i) {
//        cout << arr[i].x << " " << arr[i].y << endl;
//    }
//    cout << endl;
    LL ans = 0;
    for (int i = 1; i <= n; ++i) {
        for (int j = i + 1; j <= n; ++j) {
            struct node t[8];
            t[0].x = arr[i].y - arr[j].y + arr[i].x;
            t[0].y = arr[j].x - arr[i].x + arr[i].y;
            t[1].x = arr[j].y - arr[i].y + arr[j].x;
            t[1].y = arr[i].x - arr[j].x + arr[j].y;
//            cout << i << " " << j << endl;
//            cout << "*********" << endl;
//            for (int k = 0; k <= 1; ++k) {
//                cout << t[k].x << " " << t[k].y << endl;
//            }
//            cout << "**********" << endl;
            if (t[0].x < arr[i].x || t[0].x == arr[i].x && t[0].y < arr[i].y) {
                t[0].x = arr[j].y - arr[i].y + arr[i].x;
                t[0].y = arr[i].x - arr[j].x + arr[i].y;
            }
            if (t[1].x < arr[j].x || t[1].x == arr[j].x && t[1].y < arr[j].y) {
                t[1].x = arr[i].y - arr[j].y + arr[j].x;
                t[1].y = arr[j].x - arr[i].x + arr[j].y;
            }
            if (check(t[0], t[1], i, j)) ++ans;

            t[0].x = arr[i].y - arr[j].y + arr[i].x;
            t[0].y = arr[j].x - arr[i].x + arr[i].y;
            t[1].x = arr[j].y - arr[i].y + arr[j].x;
            t[1].y = arr[i].x - arr[j].x + arr[j].y;

            if (t[0].x > arr[i].x || t[0].x == arr[i].x && t[0].y > arr[i].y) {
                t[0].x = arr[j].y - arr[i].y + arr[i].x;
                t[0].y = arr[i].x - arr[j].x + arr[i].y;
            }
            if (t[1].x > arr[j].x || t[1].x == arr[j].x && t[1].y > arr[j].y) {
                t[1].x = arr[i].y - arr[j].y + arr[j].x;
                t[1].y = arr[j].x - arr[i].x + arr[j].y;
            }
//            for (int k = 0; k <= 1; ++k) {
//                cout << t[k].x << " " << t[k].y << endl;
//            }
//            cout << endl;
            if (check(t[0], t[1], i, j)) ans++;
        }
    }
    assert(ans >= 0);
    printf("%lld\n", ans / 4);
    return;
}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    while (scanf("%d", &n) != EOF && n) work();
    return 0;
}