#include <stdio.h>
#include <math.h>

struct adat{double x,y;};

int n,db=0;
adat a[15002];


double szam(int i,int j){
return sqrt((a[i].x-a[j].x)*(a[i].x-a[j].x)+(a[i].y-a[j].y)*(a[i].y-a[j].y));

}


bool check(int i,int j,int k){

	if((szam(i,j)==szam(j,k))&&(szam(j,k)==szam(k,i))){return true;}else{return false;}

}


int main(){
freopen("triang.in","r",stdin);
freopen("triang.out","w",stdout);
int i,j,k;
scanf("%d",&n);
for(i=1;i<=n;i++){scanf("%lf %lf",&a[i].x,&a[i].y);}

for(i=1;i<=n-2;i++)
for(j=i+1;j<=n-1;j++)
for(k=j+1;k<=n;k++)
if(check(i,j,k)){db++;}

printf("%d",db);

	return 0;}