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 p0 = 0.0;
		for(int i = 1; i <= n; i++) {
			int x = i;
			int pow = 0;
			while(x < k) {
				x *= 2;
				pow++;
			}
			p0 += (1.0/Math.pow(2.0, pow))/n;
		}
		System.out.println(p0);
	}
}
/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