import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}

void main()
{
  int n, k; readV(n, k);

  auto c(int x)
  {
    auto r = 0;
    for (; x < k; x <<= 1) ++r;
    return r;
  }

  auto p = 0.0;
  foreach (i; 1..n+1) p += 1.0 / 2^^c(i);
  writefln("%.10f", p/n);
}
