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

using namespace std;

const double eps=1.e-14;
const int INF=2<<27;

struct point{
    double x,y;
};

point v[1005];
double sol[250000];

double panta(point a,point b){
    if(fabs(a.x-b.x)<eps)
        return INF;
    return (a.y-b.y)/(a.x-b.x);
}

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

    int n,xx,yy,i,soln=0,j,r=0,st;
    point temp;

    scanf("%d",&n);

    for(i=0;i<n;++i){
        scanf("%d%d",&xx,&yy);
        temp.x=xx;
        temp.y=yy;
        v[i]=temp;
    }

    for(i=0;i<n-1;++i){
        for(j=i+1;j<n;++j){
            sol[soln+1]=panta(v[i],v[j]);
            soln++;
        }
    }

    sort(sol+1,sol+soln+1);

    for(i=1;i<soln;++i){
        st=i;
        while(fabs(sol[st]-sol[i])<eps){
            i++;
        }
        i--;
        if(i!=st){
            r=r+((i-st+1)*(i-st)/2);
        }
    }

    printf("%d\n",r);

    return 0;
}