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();
        sc.close();

        // 確率
        double prob = 0.0;
        // サイコロが1からnの場合の各確率を求め、
        // それを合計したものが求めたい確率
        for (int i = 1; i <= n; i++) {
            int points = i;
            double diff = 1.0 / n;
            while (points < k) {
                diff *= 0.5;
                points *= 2;
            }
            prob += diff;
        }
        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