#include <bits/stdc++.h>
using namespace std;
#define modulo 1000000007
#define mod(mod_x) ((((long long)mod_x+modulo))%modulo)
#define Inf 1000000000


int main(){
	
	double P,Q;
	cin>>P>>Q;
	double ok = 0.0,ng = 1e18;
	
	for(int i=0;i<100;i++){
		double mid = (ok+ng)/2.0;
		double t = P + Q*mid*log2(mid)-pow(mid,2.0);
		if(t>0.0)ok=mid;
		else ng=mid;
	}
	
	cout<<fixed<<setprecision(10)<<ok<<endl;
	
	return 0;
}