#include<bits/stdc++.h>
using namespace std;
using ll = long long;

int main()
{
	double p,q;
	cin >> p>>q;
	double l=0,r=1e18;
	for(int i = 0;i<1000;i++)
	{
		double m = (l+r)/2;
		if(p+m*q*log2(m)<m*m)
		{
			r = m;
		}
		else
		{
			l = m;
		}
	}
	printf("%.10lf\n",r);
}