import math



x, y, X, Y = [float(i) for i in input().split()]

print((math.sqrt((x-X)**2 + abs(y-Y)**2)))
import math



x, y, X, Y = [float(i) for i in input().split()]

print((math.sqrt((x-X)**2 + (y-Y)**2)))
import math

x, y, X, Y = [float(i) for i in input().split()]
print((math.sqrt((x - X) ** 2 + abs(y - Y) ** 2)))

import math

x, y, X, Y = [float(i) for i in input().split()]
print((math.sqrt((x - X) ** 2 + (y - Y) ** 2)))

-print((math.sqrt((x - X) ** 2 + abs(y - Y) ** 2))) +print((math.sqrt((x - X) ** 2 + (y - Y) ** 2)))