import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int k = in.nextInt();
        double p = 0;
        int a, c;
        for (int i = 1; i <= n; i++) {
        	a = i;
        	c = 0;
        	while (a < k) {
        		c++;
        		a *= 2;
        	}
        	p += Math.pow(0.5, c) / n;
        }
        System.out.println(p);
    }
    
}
/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