Symmetry: Convex

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문제

Given is a strictly convex polygon with nn vertices p_1,p_2,,p_np\_1, p\_2, \ldots, p\_n in counterclockwise. Denote C_iC\_i as the polygon with ii vertices p_1,p_2,,p_ip\_1, p\_2, \ldots, p\_i. For each i=3,4,,ni=3, 4, \ldots, n, find the lines which C_iC\_i is symmetric about.

입력

There are multiple test cases. The first line of input contains an integer TT (1T1051\le T\le 10^5), the number of test cases. For each test case:

The first line contains an integer nn (3n31053 \le n \le 3 \cdot 10^5), the number of vertices.

The ii-th of the following nn lines contains two integers x_ix\_i, y_iy\_i (109x_i,y_i109-10^9 \le x\_i, y\_i\le 10^9), the coordinates of p_ip\_i.

It is guaranteed that the vertices are given counterclockwise, and the polygon is strictly convex, that is, no three vertices are collinear.

It is guaranteed that the sum of nn in all test cases does not exceed 31053 \cdot 10^5.

출력

For each test case:

For each i=3,4,,ni=3, 4, \ldots, n, on the first line, output an integer kk: the number of lines which C_iC\_i is symmetric about.

In each of the following kk lines, output three integers aa, bb, cc (21018a,b,c21018-2 \cdot 10^{18} \le a, b, c \le 2 \cdot 10^{18}), denoting that C_iC\_i is symmetric about the line ax+by+c=0ax+by+c=0.

If there are multiple answers, you can output any of them. For each ii, you can output the lines in any order.