#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0, i##_len = (n); i < i##_len; i++)
#define reps(i, s, n) for(ll i = (s), i##_len = (n); i < i##_len; i++)
#define rrep(i, n) for(ll i = (n) - 1; i >= 0; i--)
#define rreps(i, e, n) for(ll i = (n) - 1; i >= (e); i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())
#define len(x) ((ll)(x).length())
#define endl "\n"

ll p, q;

double f(double n) {
    return n * n;
}

double g(double n) {
    return p + q * n * log2(n);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    // ifstream in("input.txt");
    // cin.rdbuf(in.rdbuf());
    cin >> p >> q;
    double low = 0, high = 1e12;
    rep(i, 80) {
        double mid = (low + high) / 2.0;
        if (f(mid) > g(mid)) {
            high = mid;
        }
        else {
            low = mid;
        }
    }
    printf("%.10f\n", low);
    return 0;
}