#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <cstring>
#include <string>
#include <unordered_map>
#include <cmath>
#include <assert.h>
#include <map>
#include <set>
#include <utility>

template <typename Tp>
inline void read(Tp &x) {
    x = 0;
    bool f = true; char ch = getchar();
    for ( ; ch < '0' || ch > '9'; ch = getchar()) f ^= ch == '-';
    for ( ; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + (ch ^ 48);
    x = f ? x : -x;
}

const int N = 3e3;

struct Point {
    int x, y, id;
    bool operator < (const Point &s) const {
        return (x == s.x) ? y < s.y : x < s.x;
    }
};
Point p[N + 5];

int main() {
    int T;
    read(T);
    while (T--) {
        int n;
        read(n);
        for (int i = 1; i <= 3 * n; ++i) read(p[i].x), read(p[i].y), p[i].id = i;
        std::sort(p + 1, p + 3 * n + 1);
        for (int i = 1; i <= n; ++i) printf("%d %d %d\n", p[i * 3 - 2].id, p[i * 3 - 1].id, p[i * 3].id);
    }
    return 0;
}