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#237. 三角形划分

统计

Chiaki 有 $3n$ 个点 $p_1, p_2, \dots, p_{3n}$。保证任意三点不共线。 Chiaki 想要构造 $n$ 个不相交的三角形,其中每个三角形的顶点都来自这 $3n$ 个点。

输入格式

输入包含多组测试数据。第一行包含一个整数 $T$,表示测试数据的组数。对于每组测试数据: 第一行包含一个整数 $n$ ($1 \le n \le 1000$),表示要构造的三角形数量。 接下来的 $3n$ 行,每行包含两个整数 $x_i$ 和 $y_i$ ($-10^9 \le x_i, y_i \le 10^9$)。 保证所有 $n$ 的总和不超过 $10^4$。

输出格式

对于每组测试数据,输出 $n$ 行,每行包含三个整数 $a_i, b_i, c_i$ ($1 \le a_i, b_i, c_i \le 3n$),分别表示第 $i$ 个三角形所使用的点的索引。如果存在多种解,你可以输出其中任意一种。

样例

样例输入 1

1
1
1 2
2 3
3 5

样例输出 1

1 2 3

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