import java.util.*;
import java.util.Map;
import java.util.TreeMap;
 
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++){
            double p = 1.0 / N;
            int a = i;
            for(int j=0; j<=18; j++){
                if(a>=K){
                    p *= Math.pow((double)1 / 2, j);
                    break;
                }
                a *= 2;
            }
            ans += p;
        }
        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