#include <stdio.h>
#include <stdlib.h>
#include <algorithm>

#define maxN 1010
#define x    first
#define y    second

using namespace std;

pair <int, int> panta[maxN * maxN], coord[maxN];
int N, k;

bool cmp ( pair <int, int> a, pair <int, int> b) {
        return 1LL * a.x * b.y < 1LL * b.x * a.y;
}

int main(){
        int k = 0, i, j, s = 0, t = 1;
    
        freopen("trapez.in","r",stdin);
        freopen("trapez.out","w",stdout);
    
        scanf("%d", &N);
    
        for (i = 1; i <= N; ++ i)
                scanf("%d%d", &coord[i].x, &coord[i].y);

        for (i = 1; i < N; ++ i)
                for (j = i + 1; j <= N; ++ j){
                        ++ k;
                        panta[k].x = coord[j].x - coord[i].x;
                        panta[k].y = coord[j].y - coord[i].y;
                        if (panta[k].x < 0 && panta[k].y < 0) {
                                panta[k].x = - panta[k].x;
                                panta[k].y = - panta[k].y;
                        }
                }
 
        sort (panta + 1, panta + k + 1, cmp);
    
        for (i = 1; i <= k; ++ i)
                printf("%d %d\n", panta[i].x, panta[i].y);

        t = 1;
        for (i = 1; i < k; ++ i){
                if (1LL * panta[i].x * panta[i + 1].y == 1LL * panta[i].y * panta[i + 1].x)
                        ++ t;
                else {
                        s += t * (t - 1) / 2;
                        t = 1;
                }
        }

        s += t * (t - 1) / 2;

        printf("%d\n", s);
        return 0;
}