import java.util.Scanner;

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

    double answer = 0;
    for(int i = 1; i <= n; i++) {
      int c = 0;
      int s = i;
      while(s < k) {
        s = s*2;
        c++;
      }

      double p = 1;
      for(int j = 0; j < c; j++) {
        p = p/2;
      }
      answer += p/n;
    }

    System.out.println(answer);
  }
}
/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