#include<stdio.h>
#include<math.h>
struct pct{double x,y;}a[1111],a0,a1,a2,a3,mij,d;
long n,i,st,dr,j,gas,m,nr;
long partit(pct a[ ],long st, long dr)
{long i,j,m;
 pct piv,aa;
 m=(st+dr)/2;
 piv=a[m];
 i=st-1;
 j=dr+1;
 while(1)
  {do{++i;} while(a[i].x<piv.x||(fabs(a[i].x-piv.x)<=0.00001&&a[i].y<piv.y));
   do{--j;} while(a[j].x>piv.x||(fabs(a[j].x-piv.x)<=0.00001&&a[j].y>piv.y));
   if (i<j)
	 {aa=a[i];a[i]=a[j];a[j]=aa;}
	   else
	 return j;
  }
}
void quicks(pct a[ ],long st,long dr)
{long p;
 if (st<dr)
   {p=partit(a,st,dr);
	quicks(a,st,p);
	quicks(a,p+1,dr);
   }
}
int main()
{
 freopen("patrate3.in","r",stdin);
 freopen("patrate3.out","w",stdout);
 scanf("%ld",&n);
 for(i=1;i<=n;++i)
    scanf("%lf%lf",&a[i].x,&a[i].y);
 quicks(a,1,n);
 for(i=1;i<=n;++i)
    for(j=i+1;j<=n;++j)
       if((a[i].x<a[j].x&&a[i].y>a[j].y)||(a[i].x>a[j].x&&a[i].y<a[j].y)||(fabs(a[i].x-a[j].x)<=0.00001&&fabs(a[i].y-a[j].y)<=0.00001))
       {a0=a[i];
        a1=a[j];
        mij.x=(a0.x+a1.x)/2;
        mij.y=(a0.y+a1.y)/2;
        d.x=fabs(mij.x-a0.x);
        d.y=fabs(mij.y-a0.y);
        a2.x=mij.x-d.y;
        a2.y=mij.y-d.x;
        st=1;dr=n;
        gas=0;
        while(st<=dr)
         {m=(st+dr)/2;
          if(fabs(a[m].x-a2.x)<=0.00001&&fabs(a[m].y-a2.y)<=0.00001){gas=m;break;}
          if(a[m].x<a2.x||(fabs(a[m].x-a2.x)<=0.00001&&a[m].y<a2.y))st=m+1;
                                                 else dr=m-1;}
        if(gas)
          {a3.x=mij.x+d.y;
           a3.y=mij.y+d.x;
           st=1;dr=n;
           gas=0;
           while(st<=dr)
            {m=(st+dr)/2;
             if(fabs(a[m].x-a3.x)<=0.00001&&fabs(a[m].y-a3.y)<=0.00001){gas=m;break;}
             if(a[m].x<a3.x||(fabs(a[m].x-a3.x)<=0.00001&&a[m].y<a3.y))st=m+1;
                                                    else dr=m-1;}
           if(gas)++nr;}}
 printf("%ld",nr);
 return 0;
}