#include <cstdio>

#define file_in "trapez.in"
#define file_out "trapez.out"

#define Nmax 1111

int n,i,nr,nrt,x[Nmax],y[Nmax],j;
int v1[Nmax*Nmax];
int v2[Nmax*Nmax];

inline int abs(int a) { return a>=0?a:-a; }

int main()
{
	freopen(file_in,"r",stdin);
	freopen(file_out,"w",stdout);
	
	scanf("%d", &n);
	
	for (i=1;i<=n;++i)
		 scanf("%d %d", &x[i], &y[i]);
	
	nr=0;
	
	for (i=1;i<n;++i)
		 for (j=i+1;j<=n;++j)
			  v1[++nr]=(y[j]-y[i]),
			  v2[nr]=(x[j]-x[i]);
			  
			  
		nrt=0;  
	for (i=1;i<nr;++i)
		 for (j=i+1;j<=nr;++j)
			  if (v1[i]*v2[j]==v1[j]*v2[i])
				 {
					 nrt++;
					 //printf("%d %d %d %d", v1[i],v2[i],v1[j],v2[j]);
			     }					 
	//for (i=1;i<=nr;++i)
         //printf("%d %d\n", v1[i], v2[i]);		
			  
	printf("%d", nrt);

	fclose(stdin);
	fclose(stdout);
	
	return 0;
	
}