#include<memory.h>
#include<stdlib.h>
#include<stdio.h>
#define MAX 1000
#define HMAX 0x3fffff
#define P 0x1fffff
//将每个中点的x,y都记录下来,如果
//同时记录拥有这个中点的线段的个数
struct Point{
int x;
int y;
int count;
int next;
};
Point p[MAX*MAX];
int head[HMAX];
int x[MAX],y[MAX];
int main()
{
int t,n;
int zz,xx,yy,xtmp,ytmp,ptr,res,h;
bool flag;
scanf("%d",&t);
while(t--)
{
ptr = 1;
res = 0;
memset(head,0,sizeof(head));
memset(p,0,sizeof(p));
scanf("%d",&n);
for(int i = 0; i < n; i++)
{
scanf("%d%d",&xtmp,&ytmp);
for(int j = 0; j < i; j++)
{
flag = true;
xx = xtmp + x[j];
yy = ytmp + y[j];
//h = xx & P + yy & P; --用这种方法反而更慢...
//哈希中点坐标之和
h = abs(xx + yy)%HMAX;
zz = head[h];
while(zz){
if(p[zz].x == xx && p[zz].y == yy){
p[zz].count++;
res+=p[zz].count;
flag = false;
break;
}
else
zz = p[zz].next;
}
//插入新的中点
if(flag) {
p[ptr].x = xx;
p[ptr].y = yy;
p[ptr].next = head[h];
head[h] = ptr++;
}
}
x[i] = xtmp;
y[i] = ytmp;
}
printf("%d/n",res);
}
return 0;
}