import math

a, b, c, d, e, f = map(int, input().split())

# Calculate the numerator part of the radius formula
numerator = c**2 + d**2 - 4 * a * (e - f)
denominator = 2 * abs(a)

radius = math.sqrt(numerator) / denominator

# Ensure the output has at least 15 decimal places
print("{0:.15f}".format(radius))