#include <cstdio>
#include <vector>
#include <utility>
#include <algorithm>

using namespace std;

FILE* fin=fopen("trapez.in","r");
FILE* fout=fopen("trapez.out","w");

typedef long long int64;

#define MAX 1000

vector<pair<int64,int64> > vec;
int n;
pair<int64,int64> pts[MAX];

bool comp(pair<int64,int64> p1,pair<int64,int64> p2){
	return p1.first*p2.second<p2.first*p1.second;
}

int main(){
	fscanf(fin,"%d ",&n);

	for(int i=0;i<n;i++){
		int64 x,y;
		fscanf(fin,"%lld %lld",&x,&y);
		pts[i]=make_pair(x,y);
	}

	int npx=0,npy=0;
	for(int i=0;i<n-1;i++){
		for(int j=i+1;j<n;j++){
			pair<int64,int64>p=make_pair(pts[i].second-pts[j].second,pts[i].first-pts[j].first);
			if(p.second==0){
				npy++;
			}else if(p.first==0){
				npx++;
			}else{
				vec.push_back(p);
			}
		}
	}
	sort(vec.begin(),vec.end(),comp);

	int64 res=(npy-1)*npy/2+(npx-1)*npx/2;

for(unsigned i=0;i<vec.size();i++){
		int k=0;
		while(vec[i].first*vec[i+k].second==vec[i+k].first*vec[i].second&&i+k<n){
			k++,i++;
		}
	//	printf("%d ",k);
		if(k!=0){
			res+=k*(k-1)/2;
		}
	}
	fprintf(fout,"%lld ",res);
	fclose(fin);
	fclose(fout);
	return 0;
}