#pragma GCC optimize("Ofast","unroll-loops","omit-frame-pointer","inline")
#pragma GCC option("arch=native","tune=native","no-zero-upper")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2")
#pragma GCC optimize(3)
#include<bits/stdc++.h>
#define N 3010
#define rep(i,l,r) for(int i=l;i<=r;i++)
#define drep(i,r,l) for(int i=r;i>=l;i--)
using namespace std;
int rd() {
	int res=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9') {if(ch=='-') f*=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') res=(res<<1)+(res<<3)+(ch^48),ch=getchar();
	return res*f;
}
int T,n;
struct node {
	int x,y,id;
}q[N];
bool cmp(node x,node y) {
	if(x.x!=y.x) return x.x<y.x;
	return x.y<y.y;
}
int main() {
	T=rd();
	while(T--) {
		n=rd();
		rep(i,1,n*3) q[i].x=rd(),q[i].y=rd(),q[i].id=i;
		sort(q+1,q+n*3+1,cmp);
		rep(i,1,n) printf("%d %d %d\n",q[i*3-2].id,q[i*3-1].id,q[i*3].id);
	}
	return 0;
}