836 B | 836 chars
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
BLANK = " "
inp = input
# inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = BLANK : [*map(int,inp().split(x))]
mfi = lambda x = BLANK : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
MX = 10000000
def point(info, t):
x = info[0][0] + (info[1][0] - info[0][0]) * t / MX
y = info[0][1] + (info[1][1] - info[0][1]) * t / MX
return (x, y)
def dis(a, b):
return (a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2
def solve():
l = mii()
a = [l[:2], l[4:6]]
b = [l[2:4], l[6:]]
ans = 0
for t in range(1, MX):
a_p = point(a, t)
b_p = point(b, t)
ans = max(ans, dis(a_p, b_p))
p(sqrt(ans))
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()