2011. Goat in the Garden

单点时限: 2.0 sec

内存限制: 256 MB

Someone has let a goat in a square kitchen-garden and had bound it to a stake. The stake is driven into the ground in the very midst of the square. The goat is hungry as a hunter and very voracious, and eats everything that can be reached without leaving the square and tearing the roap. What area of the kitchen-garden will be ate round?

输入格式

There are several test cases.Each contains lengths of the garden sides and a cord length in meters (natural numbers not exceeding $100$, located in one line and separated with a space).

输出格式

Should contain an area of the kitchen-garden (in square meters to within $3$ symbols after a decimal point), ate round by the goat.

样例

Input
10 6
Output
95.091

96 人解决,120 人已尝试。

121 份提交通过,共有 531 份提交。

3.6 EMB 奖励。

创建: 16 年,5 月前.

修改: 6 年,7 月前.

最后提交: 3 年,3 月前.

来源: The 3rd high school children programming contest, USU, Yekaterin