#!/usr/bin/env python3

import numpy
import scipy.optimize
import sys


def generate_func(p, q):
    def f(n):
        return p + q * n * numpy.log2(n) - numpy.square(n)
    return f


def find_root(p, q):
    sol = scipy.optimize.brentq(generate_func(p, q), 1, sys.maxsize / 10)
    return sol


def main():
    p, q = (float(z) for z in input().split())
    res = find_root(p, q)
    print("{:.8f}".format(res))


if __name__ == "__main__":
    main()