using namespace std;
#include <fstream>
#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#define NN 1505
#define EPS 0.001
#define PI 3.14159265

struct punct{
   double x,y;
   punct(){x=y=0;}
   punct(double X, double Y){ x=X, y=Y;}
   friend bool operator<(const punct &A, const punct &B){
      if(A.x+EPS< B.x)
         return 1;
      if(B.x+EPS < A.x)
         return 0;
      if(A.y+EPS<B.y)
         return 1;
      return 0;
   }
};

punct Third(punct A, punct B){
   return punct(cos(PI/3)*(A.x-B.x) - sin(PI/3)*(A.y-B.y)+B.x, sin(PI/3)*(A.x-B.x) + cos(PI/3)*(A.y-B.y)+B.y);
}

int main(){
   int n;
   double x,y;
   ifstream fin("triang.in");
   fin>>n;
   vector<punct> P;
   P.reserve(n);
   for(int i=0;i<n;++i){
      fin>>x>>y;
      P.push_back(punct(x,y));
   }
   sort(P.begin(),P.end());
   int rez=0;
   for(vector<punct>::iterator I=P.begin();I<P.end(); ++I)
      for(vector<punct>::iterator J=I+1;J<P.end();++J){
         if( binary_search(J+1,P.end(),Third(*I,*J)) )
            rez++;

      }
   ofstream fout("triang.out");
   fout<<rez;
   return 0;
}