#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#define MAXN 1111
using namespace std;
class Point{
public:
int x,y;
bool operator < (const Point &p) const{
if(x == p.x) return y < p.y;
return x < p.x;
}
bool operator == (const Point &p) const{
return x == p.x && y == p.y;
}
};
Point P[MAXN];
bool Binary_Search(const Point target,int len){
int l = 0,r = len,mid;
while(l <= r){
mid = (l+r) >> 1;
if(target == P[mid]) return true;
else if(target < P[mid]) r = mid-1;
else l = mid+1;
}
return false;
}
int main(){
int n,ans;
while(~scanf("%d",&n) && n){
for(int i = 0;i < n;i ++) scanf("%d%d",&P[i].x,&P[i].y);
sort(P,P+n);
ans = 0;
for(int i = 0;i < n;i ++){
for(int j = i+1;j < n;j ++){
Point tmp1,tmp2;
tmp1.x = P[i].x+P[i].y-P[j].y,tmp1.y = P[i].y-P[i].x+P[j].x;
tmp2.x = P[j].x+P[i].y-P[j].y,tmp2.y = P[j].y-P[i].x+P[j].x;
if(Binary_Search(tmp1,n) && Binary_Search(tmp2,n)) ans++;
}
}
printf("%d\n",ans >> 1);
}
return 0;
}