#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}


struct Precision{
  Precision(){
    cout<<fixed<<setprecision(12);
  }
}precision_beet;

//INSERT ABOVE HERE
signed main(){
  Int n;
  using D = double;
  D p,q;
  cin>>n>>p>>q;
  if(p==1){
    cout<<1.0<<endl;
    return 0;
  }
  D ap=0,aq=1;
  auto mg=[&](D p1,D q1,D p2,D q2){
            D np=p1,nq=0;
            np+=q1*p2*q1/(1.0-p1*p2);
            nq+=q1*q2/(1.0-p1*p2);
            return make_pair(np,nq);
          };
  while(n){
    if(n&1) tie(ap,aq)=mg(ap,aq,p,q);
    tie(p,q)=mg(p,q,p,q);
    n>>=1;
  }
  cout<<ap<<endl;
  return 0;
}