FENCE1 - Build a Fence

题目：有一堵无限大的墙，用长度为 $L$ 的绳子与这堵墙所能围成的区域最大面积是多少？ 输入格式：每行一个正整数 $L$（$1\leq L\leq100$），以 $0$ 结束。 输出格式：每行一个保留2位小数的正实数，不处理最后的 $0$。 样例输入： 1 0 样例输出： 0.16 感谢@qq1010903229 提供的翻译

There is a wall in your backyard. It is so long that you can’t see its endpoints. You want to build a fence of length _L_ such that the area enclosed between the wall and the fence is maximized. The fence can be of arbitrary shape, but only its two endpoints may touch the wall.

The input consists of several test cases. For every test case, there is only one integer _L_ (1<=_L_<=100), indicating the length of the fence. The input ends with _L_=0.

For each test case, output one line containing the largest area. Your answer should be rounded to 2 digits after the decimal point.

1
0

0.16