import math, strutils

let read* = iterator: string =
  while true: (for s in stdin.readLine.split: yield s)

template input*(T: static[typedesc]): untyped = 
  when T is int: read().parseInt
  elif T is float: read().parseFloat
  elif T is string: read()

let P, Q = input(float)
proc f(N: float): float =
  N * N - Q * N * log2(N) - P
var ok = 1.0
var ng = 1e20
for _ in 1 .. 100000:
  var mid = (ok + ng) / 2.0
  if f(mid) <= 0.0:
    ok = mid
  else:
    ng = mid
echo ok.formatFloat(ffDecimal, 10)