import math

a, b = map(int, input().split())

max_val = max(a, b)
min_val = min(a, b)

if a == b:
    res = math.sqrt(a ** 2 + b ** 2)
else:
    res = math.sqrt(max_val ** 2 - min_val ** 2)

print("{0:.10f}".format(res))