import math

A, B = map(int, input().split())

if A == 0 and B == 0:
    print("{0:.12f}".format(0.25))
else:
    d = math.gcd(abs(A), abs(B))
    sum_total = 0.0
    n = 0
    while True:
        denominator = d * n + 2
        exponent = denominator
        term = (n + 1) / (denominator ** exponent)
        if term < 1e-20:  # Stop when term becomes negligible
            break
        sum_total += term
        n += 1
    # Ensure sufficient precision in output
    print("{0:.12f}".format(sum_total))