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 ans = 0;
        for (int i = 1; i <= n; i++) {
            int x = i;
            int count = 0;
            while (true) {
                if (x < k) {
                    x = x << 1;
                    count++;
                } else {
                    break;
                }
            }
            ans += Math.pow(0.5, count) / n;
        }
        System.out.println(ans);
    }
}

/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