import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int k = sc.nextInt();
		double total = 0;
		for (int i = 1; i <= n; i++) {
		    int x = i;
		    double base = 1.0 / n;
		    while (x < k) {
		        x *= 2;
		        base /= 2;
		    }
		    total += base;
		}
		System.out.println(total);
   }
}

/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