import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int k = in.nextInt();

        double prob = 0;
        for (int i = 1; i <= n; i++) {
            int score = i;
            int numFlips = 0;
            while (score < k) {
                score *= 2;
                numFlips++;
            }
            prob += Math.pow(0.5, numFlips) / n;
        }

        System.out.println(prob);
    }
}

/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