#include <fstream>
#include <unordered_set>
using namespace std;

#define M 10000

struct coord {
    long long x, y;
};

unordered_set <long long> c;

int main() {
    FILE *in = fopen("patrate3.in", "r");
    FILE *out = fopen("patrate3.out", "w");
    int n, i, j;
    long long z;
    int x, y;
    fscanf(in, "%d", &n);
    coord v[n];

    for(i = 0; i < n; i ++) {
        fscanf(in, "%d.%d", &x, &y);
        v[i].x = x * M + y;
        fscanf(in, "%d.%d", &x, &y);
        v[i].y = x * M + y;
        z = v[i].x * M + v[i].y;
        c.insert(z);
    }

    coord m, c1, c2;
    int ct = 0;
    for(i = 0; i < n; i ++) {
        for(j = i + 1; j < n; j ++) {
            m.x = (v[i].x + v[j].x) / 2;
            m.y = (v[i].y + v[j].y) / 2;
            c1.x = m.x + (v[i].y - v[j].y) / 2;
            c1.y = m.y - (v[i].x - v[j].x) / 2;
            z = c1.x * M + c1.y;

            if(c.find(z) != c.end()) {
                c2.x = m.x - (v[i].y - v[j].y) / 2;
                c2.y = m.y + (v[i].x - v[j].x) / 2;
                z = c2.x * M + c2.y;

                if(c.find(z) != c.end()) {
                    //printf("%lld %lld %lld %lld %lld %lld %lld %lld\n", v[i].x, v[i].y, v[j].x, v[j].y, c1.x, c1.y, c2.x, c2.y);
                    ct ++;
                }
            }
        }
        z = v[i].x * M + v[i].y;
        c.erase(c.find(z));
    }

    fprintf(out, "%d", ct);

    return 0;
}