#include <bits/stdc++.h>
using namespace std;
const int maxn=1e3+10;
struct Point
{
int x,y,id;
bool operator< (const Point &b) const {
return x<b.x;
}
}P[maxn*3];
int n;
int main()
{
int T;
scanf("%d",&T);
while (T--)
{
scanf("%d",&n);
for (int i=1;i<=n*3;i++) scanf("%d%d",&P[i].x,&P[i].y),P[i].id=i;
sort(P+1,P+1+n*3);
for (int i=1;i<=n*3;i+=3)
printf("%d %d %d\n",P[i].id,P[i+1].id,P[i+2].id);
}
return 0;
}