import java.util.Scanner;

class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int faceNum = sc.nextInt();
        int limitScore = sc.nextInt();
        
        int face, score, cnt;
        double pr = 0;
        for(face = 1; face <= faceNum; face++){
            score = face;
            cnt = 0;
            while(score < limitScore){
                score *= 2;
                cnt++;
            }
            pr += 1 / Math.pow(2, cnt);
        }

        System.out.println(pr / faceNum);
    }
}
/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