Link: Problem - C - Codeforces
time limit per test: 2 seconds
每次测试限制时间：2 秒
memory limit per test: 64 megabytes
每次测试限制内存：64MB
input: standard input
输入：标准输入
output: standard output
输出：标准输出
Nowadays all circuses in Berland have a round arena with diameter 13 meters, but in the past things were different.
如今伯兰所有的马戏团都有一个直径13米的圆形的竞技场，但是以前有所不同。
In Ancient Berland arenas in circuses were shaped as a regular (equiangular) polygon, the size and the number of angles could vary from one circus to another.
在古伯兰，马戏团的形状是一个正多边形（等角），角的大小和数量会根据马戏团而有所不同。
In each corner of the arena there was a special pillar, and the rope strung between the pillars marked the arena edges.
竞技场的每个角落都会有一个特殊的柱子，柱子之间的绳索标记为竞技场的边界。
Recently the scientists from Berland have discovered the remains of the ancient circus arena. They found only three pillars, the others were destroyed by the time.
最近来自伯兰的科学家发现了古老的马戏团遗迹。
他们只找到了3个柱子，其他的柱子都随着时间被破坏了。
You are given the coordinates of these three pillars. Find out what is the smallest area that the arena could have.
给定3根柱子的坐标。找出竞技场可以有的最小范围。
Input
输入
The input file consists of three lines, each of them contains a pair of numbers –– coordinates of the pillar.
输入文件由3行组成，每行包含一对数字----柱子的坐标。
Any coordinate doesn't exceed 1000 by absolute value, and is given with at most six digits after decimal point.
所有坐标的绝对值不超过1000，并且最多以6位小数给出。
Output
输出
Output the smallest possible area of the ancient arena.
输出可能最小的古代竞技场的范围。
This number should be accurate to at least 6 digits after the decimal point.
这个数应该精确到小数点后6位。
It's guaranteed that the number of angles in the optimal polygon is not larger than 100.
保证最优多边形的角的数量不会超过100.
Examples
例子
input
输入
0.000000 0.000000 1.000000 1.000000 0.000000 1.000000
output
输出
1.00000000
