
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		int K = sc.nextInt();

		double dice=1/(double)N;
		double ans=0;

		for(int i=1;i<=N;i++) {
			int n=i;
			double m=dice;
			while(n<K) {
				n *= 2;
				m /= 2.0;
			}
			ans += m;
		}

		System.out.println(ans);

	}


}
/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