#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define endl '\n'
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rep2(i,a,b) for(int i=int(a);i<int(b);i++)
#define pb emplace_back
#define all(x) (x).begin(),(x).end()
ll mod=1e9+7;
ll mod2=998244353;
const int INF=1e9;

signed main(){
   double n,k;
   cin>>n>>k;
   
   double ans=0;
   rep2(i,1,n+1){
      double tmp=1.0/n;
      ll x=i;
      while(x<k){
         x*=2;
         tmp/=2;
      }
      ans+=tmp;
   }
   cout<<fixed<<setprecision(20)<<ans<<endl;
}


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