#include <cstdio>
#include <cmath>
#include <algorithm>
#define MAXN 1000
#define MAXDR 500000
using namespace std;

const double INF=2.e9;
const double eps=1.e-14;
struct POINT{
    int x, y;
}v[MAXN+5];
double p[MAXDR];

double panta(POINT P1, POINT P2){
    if (fabs(P1.x-P2.x)<eps)
        return INF;
    else return 1.0*(P2.y-P1.y)/(P2.x-P1.x);
}

bool cmp(double a, double b){
    return (a-b<=-eps);
}

int main(){
    freopen("trapez.in", "r", stdin);
    freopen("trapez.out", "w", stdout);
    int n, i, j, k, lg, ans;
    double pred;
    scanf("%d", &n);
    for (i=1; i<=n; i++)
        scanf("%d%d", &v[i].x, &v[i].y);
    k=0;
    for (i=1; i<=n-1; i++)
        for (j=i+1; j<=n; j++)
            p[++k]=panta(v[i], v[j]);
    sort(p+1, p+k+1, cmp);
    pred=p[1];
    lg=1;
    ans=0;
    for (i=2; i<=k; i++){
        if (fabs(p[i]-pred)<eps){
            lg++;
        }
        else{
            ans+=lg*(lg-1)/2;
            lg=1;
            pred=p[i];
        }
    }
    printf("%d", ans);
    return 0;
}