#P989E. A Trance of Nightfall

    ID: 5367 Type: RemoteJudge 2000ms 256MiB Tried: 0 Accepted: 0 Difficulty: 10 Uploaded By: Tags>dpgeometrymatricesprobabilities*2700

A Trance of Nightfall

Description

The cool breeze blows gently, the flowing water ripples steadily.

"Flowing and passing like this, the water isn't gone ultimately; Waxing and waning like that, the moon doesn't shrink or grow eventually."

"Everything is transient in a way and perennial in another."

Kanno doesn't seem to make much sense out of Mino's isolated words, but maybe it's time that they enjoy the gentle breeze and the night sky — the inexhaustible gifts from nature.

Gazing into the sky of stars, Kanno indulges in a night's tranquil dreams.

There is a set SS of nn points on a coordinate plane.

Kanno starts from a point PP that can be chosen on the plane. PP is not added to SS if it doesn't belong to SS. Then the following sequence of operations (altogether called a move) is repeated several times, in the given order:

  1. Choose a line ll such that it passes through at least two elements in SS and passes through Kanno's current position. If there are multiple such lines, one is chosen equiprobably.
  2. Move to one of the points that belong to SS and lie on ll. The destination is chosen equiprobably among all possible ones, including Kanno's current position (if it does belong to SS).

There are qq queries each consisting of two integers (ti,mi)(t_i, m_i). For each query, you're to help Kanno maximize the probability of the stopping position being the tit_i-th element in SS after mim_i moves with a proper selection of PP, and output this maximum probability. Note that according to rule 1, PP should belong to at least one line that passes through at least two points from SS.

The first line contains a positive integer nn (2n2002 \leq n \leq 200) — the number of points in SS.

The ii-th of the following nn lines contains two space-separated integers xix_i and yiy_i (104xi,yi104-10^4 \leq x_i, y_i \leq 10^4) — the coordinates of the ii-th point in SS. The input guarantees that for all 1i<jn1 \leq i \lt j \leq n, (xi,yi)(xj,yj)(x_i, y_i) \neq (x_j, y_j) holds.

The next line contains a positive integer qq (1q2001 \leq q \leq 200) — the number of queries.

Each of the following qq lines contains two space-separated integers tt and mm (1tin1 \leq t_i \leq n, 1mi1041 \leq m_i \leq 10^4) — the index of the target point and the number of moves, respectively.

Output qq lines each containing a decimal number — the ii-th among them denotes the maximum probability of staying on the tit_i-th point after mim_i steps, with a proper choice of starting position PP.

Your answer will be considered correct if each number in your output differs from the corresponding one in jury's answer by at most 10610^{-6}.

Formally, let your answer be aa, and the jury's answer be bb. Your answer is considered correct if ab106|a - b| \le 10^{-6}.

Input

The first line contains a positive integer nn (2n2002 \leq n \leq 200) — the number of points in SS.

The ii-th of the following nn lines contains two space-separated integers xix_i and yiy_i (104xi,yi104-10^4 \leq x_i, y_i \leq 10^4) — the coordinates of the ii-th point in SS. The input guarantees that for all 1i<jn1 \leq i \lt j \leq n, (xi,yi)(xj,yj)(x_i, y_i) \neq (x_j, y_j) holds.

The next line contains a positive integer qq (1q2001 \leq q \leq 200) — the number of queries.

Each of the following qq lines contains two space-separated integers tt and mm (1tin1 \leq t_i \leq n, 1mi1041 \leq m_i \leq 10^4) — the index of the target point and the number of moves, respectively.

Output

Output qq lines each containing a decimal number — the ii-th among them denotes the maximum probability of staying on the tit_i-th point after mim_i steps, with a proper choice of starting position PP.

Your answer will be considered correct if each number in your output differs from the corresponding one in jury's answer by at most 10610^{-6}.

Formally, let your answer be aa, and the jury's answer be bb. Your answer is considered correct if ab106|a - b| \le 10^{-6}.

Sample Input 1

5
0 0
1 3
2 2
3 1
4 4
10
1 1
2 1
3 1
4 1
5 1
3 2
3 3
3 4
3 5
3 6

Sample Output 1

0.50000000000000000000
0.50000000000000000000
0.33333333333333331483
0.50000000000000000000
0.50000000000000000000
0.18518518518518517491
0.15226337448559670862
0.14494741655235482414
0.14332164812274550414
0.14296036624949901017

Note

The points in SS and possible candidates for line ll are depicted in the following figure.

For the first query, when P=(1,3)P = (-1, -3), ll is uniquely determined to be 3x=y3x = y, and thus Kanno will move to (0,0)(0, 0) with a probability of 12\frac 1 2.

For the third query, when P=(2,2)P = (2, 2), ll is chosen equiprobably between x+y=4x + y = 4 and x=yx = y. Kanno will then move to the other four points with a probability of 1213=16\frac 1 2 \cdot \frac 1 3 = \frac 1 6 each, or stay at (2,2)(2, 2) with a probability of 13\frac 1 3.