import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int N = in.nextInt();
		int K = in.nextInt();
		double ans = 0;
		for (int i = 1; i <= N; i++) {
			double tmp = 1.0 / N;
			int now = i;
			while (now < K) {
				now *= 2;
				tmp /= 2;
			}
			ans += tmp;
		}
		System.out.println(String.format("%.12f", ans));
		in.close();
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz