import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();	//サイコロの面の数
		int K = sc.nextInt();	//得点
		double d = 0.0;	//勝つ確率
		int coin = 0;	//コインの回数記録
		int calc = 0;	//コインの回数計算
		for(int i = 1; i <= N; i++) {
			calc = i; coin = 0;
			for(;calc < K;coin++) calc *= 2;
			d += (1.0/N) * Math.pow((1.0/2), coin);
		}
		System.out.println(d);
	}

}
/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