from decimal import Decimal, getcontext, ROUND_HALF_UP

# Set precision and rounding mode to handle accurate decimal operations
getcontext().prec = 20
getcontext().rounding = ROUND_HALF_UP

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

if a != b:
    c = max(a, b)
    d = min(a, b)
    # Calculate c² - d² using Decimal for high precision
    cs = Decimal(c)
    ds = Decimal(d)
    res = (cs**2 - ds**2).sqrt()
else:
    # Calculate hypotenuse when both sides are equal
    res = (Decimal(a)**2 * 2).sqrt()

# Format the result to 10 decimal places
formatted_res = res.quantize(Decimal('1.0000000000'))
print(f"{formatted_res:.10f}")