import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] tmp = br.readLine().split(" ");

		int N = Integer.parseInt(tmp[0]);
		int K = Integer.parseInt(tmp[1]);

		double ans = 0;

		for (long  i = 1; i <= N; i++) {
			// iはさいころの目

			if (i >= K) {
				ans += 1.0/N;
			} else {
				int rp = 1;
				long point = i * 2;
				while (K > point) {
					rp++;
					point *= 2;
				}

				ans += 1.0 / (Math.pow(2, rp) * N);
			}
		}

		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