#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<long double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};

int n=14,m,S;
double A,B,C;

inline long double f(int I,int J){
	long double p=1;
	for(int i=0;i<n;i++) if(I&1<<i){
		int t=0;
		bool F=(J&1<<i?1:0);
		if(i&&I&1<<(i-1)) t++;
		if(i<n-1&&I&1<<(i+1)) t++;
		if(t==0) p*=(F?1-A:A);
		if(t==1) p*=(F?1-B:B);
		if(t==2) p*=(F?1-C:C);
	}
	return p;
}

int main(){
	cin>>m>>A>>B>>C;
	A/=100,B/=100,C/=100;
	S=1<<n;
	vd dp(S),a;
	dp[S-1]=1;
	for(int i=0;i<S;i++){
		int I=i;
		while(I){
			a.push_back(f(i,I));
			I=(I-1)&i;
		}
		a.push_back(f(i,0));
	}
	for(int i=0;i<80-m;i++){
		vd DP(1<<n);
		int id=0;
		for(int j=0;j<S;j++){
			int I=j;
			while(I){
				DP[I]+=a[id++]*dp[j];
				I=(I-1)&j;
			}
			DP[0]+=a[id++]*dp[j];
		}
		dp=DP;
	}
	long double res=0;
	for(int i=0;i<S;i++){
		long double t=0;
		for(int j=0;j<n;j++) if(i&1<<j) t+=1;
		res+=t*dp[i];
	}
	cout<<syosu(9)<<2*res<<endl;
}