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 count = n;
          int point = i;
          while(point<k){count*=2;point*=2;}
          double ans2 = 1.0/count;ans+=ans2;}        
	    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