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 pt = i;
      for(int j = 0;;j++){
        if(pt>=k){
          ans += Math.pow(0.5,j);
          break;
        }else{
          pt = pt*2;
        }
        
      }
    }
    ans = ans/n;
    System.out.println(String.format("%.10f", 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