#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 1010

vector<pair<int64,int64> > vec,pts;
int n;

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

void prep_frac(pair<int64,int64>& p){
	if(p.second<0){
		p.second=abs(p.second);
		p.first*=-1L;
	}
}
int main(){
	fscanf(fin,"%d ",&n);
	pts.resize(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{
				prep_frac(p);
				vec.push_back(p);
			}
		}
	}
	
	vec.push_back(make_pair(0x3f3f3f3f,0x3f3f3f3f));
	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+1].sescond==vec[i+1].first*vec[i].second&&i+1<vec.size()){
			k++,i++;
		}
		if(k!=0){
			res+=k*(k+1)/2;
		}
	}

	fprintf(fout,"%lld ",res);

	fclose(fin);
	fclose(fout);
	return 0;
}