#include<bits/stdc++.h>
#define double long double
#define int long long
using namespace std;
struct node {
	double wt;
	int cnt;
	node(double w,int c) { wt=w,cnt=c; }
	inline friend bool operator <(const node &A,const node &B) {
		return A.wt>B.wt;
	}
};
int fac[21];
double pw[21][4];
signed main() {
	int n;
	scanf("%lld",&n);
	for(int t:{0,1,2,3}) {
		pw[0][t]=1;
		scanf("%Lf",&pw[1][t]);
		for(int i=2;i<=n;++i) pw[i][t]=pw[1][t]*pw[i-1][t];
	}
	priority_queue <node> Q;
	fac[0]=1;
	for(int i=1;i<=n;++i) fac[i]=fac[i-1]*i;
	for(int a=0;a<=n;++a) {
		for(int b=0;a+b<=n;++b) {
			for(int c=0;a+b+c<=n;++c) {
				int d=n-a-b-c;
				Q.push(node(pw[a][0]*pw[b][1]*pw[c][2]*pw[d][3],fac[n]/fac[a]/fac[b]/fac[c]/fac[d]));
			}
		}
	}
	double ans=0;
	while(!Q.empty()) {
		auto x=Q.top(); Q.pop();
		if(x.cnt==1) {
			if(Q.empty()) break;
			auto y=Q.top(); Q.pop();
			Q.push(node(x.wt+y.wt,1));
			ans+=x.wt+y.wt;
			if(y.cnt>1) Q.push(node(y.wt,y.cnt-1));
		} else {
			ans+=(x.wt*2)*(x.cnt/2);
			Q.push(node(x.wt*2,x.cnt/2));
			if(x.cnt%2!=0) Q.push(node(x.wt,x.cnt%2));
		}
	}
	printf("%.10Lf\n",ans);
	return 0;
}