Problem: Snuke received a triangle as a birthday present. The coordinates of the three vertices were (x_1, y_1), (x_2, y_2), and (x_3, y_3).

He wants to draw two circles with the same radius inside the triangle such that the two circles do not overlap (but they may touch). Compute the maximum possible radius of the circles.

Constraints

* 0 ≤ x_i, y_i ≤ 1000
* The coordinates are integers.
* The three points are not on the same line.

Input

The input is given from Standard Input in the following format:


x_1 y_1
x_2 y_2
x_3 y_3


Output

Print the maximum possible radius of the circles. The absolute error or the relative error must be at most 10^{-9}.

Examples

Input

0 0
1 1
2 0


Output

0.292893218813


Input

3 1
1 5
4 9


Output

0.889055514217

Solution (in PYTHON3):

Solution:
# -*- coding: utf-8 -*-

import sys
from math import hypot, sqrt

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

def heron(a, b, c):
    s=(a+b+c)/2
    return sqrt(s*(s-a)*(s-b)*(s-c))

x1,y1=MAP()
x2,y2=MAP()
x3,y3=MAP()

# 各辺の長さ
a=hypot(x1-x2, y1-y2)
b=hypot(x2-x3, y2-y3)
c=hypot(x3-x1, y3-y1)
# 三角形の面積(ヘロンの公式)
S=heron(a, b, c)
# 内接円の半径
r=2*S/(a+b+c)

# max(a,b,c)*(1-x/r)==2*xをxについて解く
mx=max(a, b, c)
print(mx/(2+mx/r))