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

int main(){
    double P, Q;
    cin >> P >> Q;
    double ng = 1e18, ok = 1;
    for(int t=0; t<200; t++){
        double N = (ng+ok)/2;
        double res = P + Q*N*log2(N) - N*N;
        (res >= 0 ? ok : ng) = N;
    }
    cout << fixed << setprecision(10) << ok << endl;
    return 0;
}