import core.bitop, std.algorithm, std.ascii, std.bigint, std.conv, std.math,
    std.functional, std.numeric, std.range, std.stdio, std.string, std.random,
    std.typecons, std.container;

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

alias sread = () => readln.chomp();
enum MOD = 10 ^^ 9 + 7;

void main()
{
    long N, K;
    scan(N, K);
    double ans = 0.0;
    foreach (n; 1 .. N + 1)
    {
        long tmp = n;
        long cnt = 0;
        while (tmp < K)
        {
            cnt++;
            tmp *= 2;
        }
        // writeln(cnt);
        ans += (1.0 / N) * (1.0 / (2 ^^ cnt));
    }
    writefln("%.10f", ans);
}
