import java.util.Scanner;
public class Main{

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		double n = sc.nextDouble();
		double k = sc.nextDouble();
		
		double E = 0;
		double q;
		for(double p = 1; p <= n; p++) {
			double Ep = 1/n;
			q = p;
			if(p >= k) {
				E += Ep;
			}
			if(p < k) {
				do{
					q = q * 2;
					Ep = Ep / 2;
				}while(q < k);
				
				E += Ep;
			}
		}
		System.out.println(E);

	}

}

/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