import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scn = new Scanner(System.in);
		int n = scn.nextInt();
		int k = scn.nextInt();
		int count = 0;
		double ans = 0;
		for (int i = 1; i <= n; i++) {
			int j = 0;
			count = i;
			for(;count<k;j++) {
				count *=2;
			}
			ans += 1.0 / (n * Math.pow(2,j));
		}
		System.out.println(ans);
		scn.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