Thanks_up与出租车

Thanks_up昨天晚上熬夜休闲打CF，然后今天早上起晚了，这是真的惨啊

现在他要赶车去相亲，，

他所在的位置是坐标平面的点（a，b）。在他的app上面周围有n个出租车司机， 第i辆出租车位于（xi，yi）点，以vi的速度移动。

现在每个出租车司机都会以最快的速度朝Thanks_up那边开，请问Thanks_up会最快坐上哪辆出租车

The first line of the input contains two integers a and b ( - 100 ≤ a, b ≤ 100) — coordinates of Vasiliy's home.

The second line contains a single integer n (1 ≤ n ≤ 1000) — the number of available Beru-taxi cars nearby.

The i-th of the following n lines contains three integers x_i, y_i and v_i ( - 100 ≤ x_i, y_i ≤ 100, 1 ≤ v_i ≤ 100) — the coordinates of the i-th car and its speed.

It's allowed that several cars are located at the same point. Also, cars may be located at exactly the same point where Vasiliy lives.

第一行输入两个整数a and b ( - 100 ≤ a, b ≤ 100) ，代表Thanks_up的位置

第二行输入一个整数n (1 ≤ n ≤ 1000)，附近出租车的数量

接下来有n行，每i行都要三个整数x_i, y_i and v_i ( - 100 ≤ x_i, y_i ≤ 100, 1 ≤ v_i ≤ 100) ，代表第i辆出租车的位置以及他的速度

允许一个点有多辆出租车，且出租车可能就在Thanks_up的位置

Print a single real value — the minimum time Vasiliy needs to get in any of the Beru-taxi cars. You answer will be considered correct if its absolute or relative error does not exceed 10^- 6.

Namely: let's assume that your answer is a, and the answer of the jury is b. The checker program will consider your answer correct, if .

输出Thanks_up坐上出租车的最短时间，误差在10^- 6内即算做正确

0 0
2
2 0 1
0 2 2

1.00000000000000000000

1 3
3
3 3 2
-2 3 6
-2 7 10

0.50000000000000000000

 Note

In the first sample, first taxi will get to Vasiliy in time 2, and second will do this in time 1, therefore 1 is the answer.
In the second sample, cars 2 and 3 will arrive simultaneously.