import java.util.*;
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 score=i;
			double bunbo=n;
			double ans2=1/bunbo;
			int count=0;
			while(true){
				if(score<k){
					score*=2;
					count++;
					ans2*=0.5;
				}else
					break;
			}
			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