import std;

double calc(double p, double q) {
    double lo = 0;
    double hi = 1e12;
    double ans = 0;
    foreach (_; 0..100) {
        auto m = (lo + hi) / 2;
        if (m * m <= p + q * m * log2(m)) {
            ans = max(ans, m);
            lo = m;
        } else hi = m;
    }
    return ans;
}

void main() {
    double p, q; scan(p, q);
    writefln("%.10f", calc(p, q));
}

void scan(T...)(ref T a) {
    string[] ss = readln.split;
    foreach (i, t; T) a[i] = ss[i].to!t;
}
T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;