from math import sqrt

x1, y1, x2, y2 = list(map(float, input().split()))

r = sqrt((x1 - x2)**2 + (y1 - y2)**2 )

print(('{0:.5f}'.format(r)))

from math import sqrt

x1, y1, x2, y2 = list(map(float, input().split()))

r = sqrt((x1 - x2)**2 + (y1 - y2)**2 )

print(r)

from math import sqrt

x1, y1, x2, y2 = list(map(float, input().split()))
r = sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(("{0:.5f}".format(r)))

from math import sqrt

x1, y1, x2, y2 = list(map(float, input().split()))
r = sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print(r)

-print(("{0:.5f}".format(r))) +print(r)