#include <fstream>
#include <cmath>
#include <algorithm>
using namespace std;

struct pct{ double x,y;}a[1503];
int n;

double dist(pct x,pct y)
{
       return (x.x-y.x)*(x.y-y.x);
}
bool cmp(pct x,pct y)
{
     return x.x>y.x;
}

int main()
{
    int i,nrt=0,j,k;
    ifstream in("triang.in");
    ofstream out("triang.out");
    in>>n;
    for(i=0;i<n;i++)
    in>>a[i].x>>a[i].y;
    in.close();
    sort(a,a+n,cmp);
    for(i=0;i<n;i++)
    for(j=i+1;j<n;j++)
    for(k=j+1;k<n&& dist(a[i],a[j])==dist(a[k],a[j])==dist(a[i],a[k]);k++)
    nrt++;
    out<<nrt<<'\n';
    out.close();
    return 0;
}