import java.util.*;
class Main {
  public static void main(String[] args) {
    Scanner stdIn = new Scanner(System.in);
    int n = stdIn.nextInt();
    int k = stdIn.nextInt();
    double per = 0;
    int[] a = new int[n];
    double[] b = new double[n];
    for(int i = 0;i<a.length;i++) {
      a[i] = i+1;
    }
    for(int i = 0;i<a.length;i++) {
      int count = a[i];
      b[i] = 1.0/n;
      for(;count<k;count*=2) {
        b[i] = b[i]*1/2;
      }
    }
    double sum = 0;
    for(int i = 0;i<b.length;i++) {
      sum += b[i];
    }
    System.out.println(sum);
  }
}

/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