#include <cstdio>
#include <math.h>

using namespace std;

#define Nmax 1024

int n, x[Nmax], y[Nmax], nr;
float p[Nmax*Nmax];

void qsort(int st,int dr)
{
     int i=st,j=dr;
     float tmp, sch = p[(i+j)/2];
     do
     {
          while (p[i] < sch) ++i;
          while (p[j] > sch) --j;
          if (i<=j) 
          {
               tmp = p[i];
               p[i] = p[j];
               p[j] = tmp;
               ++i; --j;                    
          }     
     } while (i<=j);
     if (st<j) qsort(st,j);
     if (i<dr) qsort(i,dr);
}

int main()
{
     freopen("trapez.in","r",stdin);
     freopen("trapez.out","w",stdout);

     scanf("%d", &n);

     for (int i=1;i<=n;++i)
     {
          scanf("%d%d", x+i,y+i);
          for (int j=1;j<i;++j)
              p[++nr] = atan2((float)y[i]-(float)y[j],(float)x[i]-(float)x[j]);
     }
     
     qsort(1,nr);

     long long tmp = 0, ret = 0, a,b,c;
     
     p[0] = -666;     
     for (int i=1;i<=nr;++i)
          if (p[i]!=p[i-1])
          {
               a = tmp;
               b = a-1;
               c = a;
               c *= b;
               c = c/2;
               if (c>0)
                    ret += c;
               tmp = 0;          
          }
               else
     ++tmp;
     a = tmp;
     b = a-1;
     c = a*b;
     c = c/2;
     if (c>0)
          ret += c;
               
     printf("%lld\n", ret);

     return 0;
}