import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int p = sc.nextInt();
		int q = sc.nextInt();
		sc.close();

		double ok = 1;
		double ng = 1e18;
		for (int i = 0; i < 200; i++) {
			double mid = (ok + ng) / 2;
			if (calc(mid, q) <= p) {
				ok = mid;
			} else {
				ng = mid;
			}
		}
		System.out.println(ok);
	}

	static double calc(double mid, int q) {
		BigDecimal bn = BigDecimal.valueOf(mid);
		BigDecimal bq = BigDecimal.valueOf(q);
		BigDecimal bln = BigDecimal.valueOf(Math.log10(mid) / Math.log10(2));
		return bn.multiply(bn.subtract(bq.multiply(bln))).doubleValue();
	}
}