import java.time.Instant;
import java.util.*;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int K = sc.nextInt();

		int[] cnt = new int[N];
		for(int i=0; i<N; i++){
			int c = 0;
			int n = i+1;
			while(n<K) {
				n= n*2;
				c++;
			}
			cnt[i]=c;
		}

		Double ans = 0.0;

		for(int i=0; i<N; i++) {
			ans += (double) 1 / N * (double) (1 / Math.pow(2, cnt[i]));
		}

		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