#include<iostream>
#include <bits/stdc++.h>

#define ld long double
#define ll long long
#define rep(i, a, b) for(int i = a ; i < b ; i ++)
#define sz(v) (int)v.size()
#define all(v) begin(v), end(v)
#define IO ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
const int N = 22;
int ncr[N][N];

void preprocess() {
    for (int i = 0; i < N; i++) {
        for (int j = 0; j <= i; j++) {
            if (j == 0)ncr[i][j] = 1;
            else {
                ncr[i][j] = ncr[i - 1][j] + ncr[i - 1][j - 1];
            }
        }
    }
}

void doWork() {
    int n;
    cin >> n;
    ld a, b, c, d;
    cin >> a >> b >> c >> d;
    ll ee = 0;
    priority_queue<pair<ld, ll>, vector<pair<ld, ll>>, greater<pair<ld, ll>>> q;
    for (int i = 0; i <= n; i++) {
        for (int j = 0; j <= n; j++) {
            for (int k = 0; k <= n; k++) {
                for (int z = 0; z <= n; z++) {
                    if (i + j + k + z != n)continue;
                    ll cnt = 1ll * ncr[n][i] * ncr[n - i][j] * ncr[n - i - j][k] * ncr[n - i - j - k][z];
                    ee += cnt;
                    ld p = 1;
                    for (int f = 1; f <= i; f++)p *= a;
                    for (int f = 1; f <= j; f++)p *= b;
                    for (int f = 1; f <= k; f++)p *= c;
                    for (int f = 1; f <= z; f++)p *= d;
                    q.push({p, cnt});
                }
            }
        }
    }
    ld ans = 0;
    while (q.size() > 1 || q.top().second > 1) {
        pair<ld, ll> x = q.top();
        q.pop();
        if (x.second == 1) {
            pair<ld, ll> y = q.top();
            q.pop();
            if (y.second - 1 > 0) {
                q.push({y.first, y.second - 1});
            }

            ans += x.first + y.first;
            q.push({x.first + y.first, 1});
            continue;
        }
        ans += x.first * (x.second / 2) * 2;
        q.push({x.first * 2, x.second / 2});
        if (x.second % 2) {
            q.push({x.first, 1});
        }
    }
    cout << fixed << setprecision(9) << ans;
}

int main() {
//    IO
    preprocess();
    int t = 1;
//    cin >> t;
    for (int i = 1; i <= t; i++) {
        //  cout << "Case #" << i << ": ";
        doWork();
    }
}