import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        int k = Integer.parseInt(sc.next());
        double p = Math.pow(n, -1);
        double ans = 0;
        for (int i = 0; i < n; i++) {
            if (i + 1 > k) {
                ans += 1;
            } else {
                double pow = Math.log(k / (i + 1.0)) / Math.log(2);
                ans += Math.pow(0.5, Math.ceil(pow));
            }
        }
        System.out.println(ans * 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