import math

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

def compute_sum(A, B):
    if A == 0 and B == 0:
        return 0.25  # Only the initial position (1,1) is reachable
    
    d = math.gcd(abs(A), abs(B))
    if d == 0:
        return 0.25  # This case is redundant as d is at least 1 if A or B is non-zero
    
    res = 0.0
    m = 0
    while True:
        k = 2 + d * m
        term = (m + 1) / (k ** k)
        res += term
        if term < 1e-20:  # Term is small enough to stop
            break
        m += 1
    return res

result = compute_sum(A, B)
# Formatting the output to have enough decimal places and trimming trailing zeros
formatted_result = "{0:.30f}".format(result).rstrip('0').rstrip('.') if '.' in "{0:.30f}".format(result) else "{0:.30f}".format(result)
print(formatted_result)