import java.util.*;
class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        double n = scanner.nextDouble();
        int k = scanner.nextInt();
        double ans = 0.0;
        for(int i = 1; i <= n; i++){
            int p = 0;
            double cur = i;
            while(cur < k){
                cur *= 2;
                p++;
            }
            ans += Math.pow(0.5, p) * 1 / 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