import java.io.*;
import java.util.*;


public class Main_yukicoder425 {

	private static Scanner sc;
	private static Printer pr;

//	private static int p;
	private static int q;

	private static void solve() {
		int p = sc.nextInt();
		q = sc.nextInt();

		double ret = (double)1 / 3;

		pr.printf("%.7f\n", ret + f(p, (double)1 / 3));
	}

	private static double f(int p, double d) {
		double EPS = 1.e-10;
//		pr.println(d);
		if (d < EPS) {
			return 0;
		}
		double ret = d * p / 100 / 2 + d * (100 - p) / 100 / 3;
		ret += f(Math.max(0, p - q), d * p / 100 / 2);
		ret += f(Math.min(100, p + q), d * (100 - p) / 100 / 3);

		return ret;
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}