A, B, C, D, E, F = map(int, input().split())

if A != B:
    raise ValueError
# x^2 + cx + y^2 + dy = f に直す
C /= A
D /= A
F = (F - E) / A

print((F + (C / 2) ** 2 + (D / 2) ** 2) ** .5)