#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;


#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<typename T,typename U> 
using gmap = cc_hash_table<T, U, hash<T> >;

//INSERT ABOVE HERE
signed main(){
  using D = double;
  using M = gmap<int, D>;
  int a;
  cin>>a;
  a=80-a;
  
  D p[3];
  for(int i=0;i<3;i++) cin>>p[i],p[i]/=100;

  const int t=14;
  int s=1<<t;
  
  vector<M> co(s);

  vector<vector<int> > vs(s,vector<int>(t+2));
  for(int b=0;b<s;b++)
    for(int i=0;i<t;i++)
      vs[b][i+1]=(b>>i)&1;
  
  for(int b=0;b<s;b++){
    vector<D> po(t);
    for(int i=0;i<t;i++){
      if((~b>>i)&1) continue;
      po[i]=p[vs[b][i]+vs[b][i+2]];
    }
    
    for(int nb=b;nb;nb=(nb-1)&b){
      D &res=co[b][nb];
      res=1.0;      
      for(int i=0;i<t;i++){
        if((~b>>i)&1) continue;
        if((~nb>>i)&1) res*=po[i];
        else res*=1.0-po[i];
      }
    }
  }
  
  vector<D> dp(s,0);
  dp[s-1]=1.0;
  
  for(int i=0;i<a;i++){
    vector<D> nx(s,0);
    for(int b=0;b<s;b++)
      for(int nb=b;nb;nb=(nb-1)&b)
        nx[nb]+=dp[b]*co[b][nb];
    swap(dp,nx);
  }  
  
  D ans=0;
  for(int b=0;b<s;b++)
    ans+=__builtin_popcount(b)*dp[b];

  cout<<ans*2<<endl;
  return 0;
}