import java.util.*;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

        double n = sc.nextInt();
		double k = sc.nextInt();
		
		double rate = 0;
		int score = 0;

		for (int i = 0; i < n; i++) {
			score = i + 1;
			if (score < k) {
				int count = 0;
				while (score < k) {
					count++;
					score *= 2;
				}
				rate += (1/n) * Math.pow(0.5, count);
			} else {
				rate += 1 / n;
			}
		}

		System.out.println(rate);
	}
}
/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