Перевести программу из питона на с# from math import sqrt as sqrt
x1, y1, x2, y2, x3, y3 = list(map(int,input().split()))
a = sqrt((x2-x1)**2 + (y2-y1)**2)
b = sqrt((x3-x2)**2 + (y3-y2)**2)
c = sqrt((x1-x3)**2 + (y1-y3)**2)
p = (a+b+c)/2
S = sqrt(p*(p-a)*(p-b)*(p-c))
R = round((a*b*c)/(4*S),3)
print(R)