#include<fstream.h>
#include<math.h>
double a[1500],b[1500];
int N;
void citire(){
ifstream fin("triang.in");
fin>>N;
for (int i=0;i<N;i++)
   fin>>a[i]>>b[i];
fin.close();
}
double latura(double x1,double y1,double x,double  y){
double w=0;
w+=(x1-x);
w*=(x1-x);
w+=(y1-y)*(y1-y);
double f=sqrt(w);
return f;
}
int numarare (){
double L,L1,L2;
int nr=0;
for (int i=0;i<N-2;i++)
     for (int j=i+1;j<N-1;j++){
	L=latura(a[i],b[i],a[j],b[j]);
	 for (int y=j+1;y<N;y++){
	 L1=latura(a[i],b[i],a[y],b[y]);
	 L2=latura(a[y],b[y],a[j],b[j]);
	 if (L2+0.1>L1&&L2-0.1<L1)
	 if (L1+0.1>L&&L1-0.1<L)
	    nr++;}}
return nr;

}
int main(){
citire();
ofstream fout("triang.out");
fout<<numarare();
fout<<"\n";
fout.close();
return 0;
}