//
// Stvoreno ENERGom o 09.04.24. 14:46:54
//

#include<bits/stdc++.h>

#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define MP make_pair
#define pb push_back
#define PB push_back
#define F first
#define fir first
#define S second
#define sec second

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef __float128 ld;

#ifdef Energy
#define DEBUG for (int ____DEBUG=1;____DEBUG;____DEBUG=0)

template<class ...Ts>
auto &PRNT(Ts ...ts) { return ((cerr << ts << " "), ...); }

#define LOG(...) PRNT(#__VA_ARGS__" ::",__VA_ARGS__)<<endl
#else
#define DEBUG while(0)
#define LOG(...)
#endif

const int max_n = 22, inf = 1000111222;

int n;
long double p[4];
ll c[max_n][max_n];

ll calc_ways(int A, int B, int C, int D) {
    return c[n][A] * c[n - A][B] * c[n - A - B][C];
}

ld mypow(ld x, int n) {
    ld res = 1;
    while (n--) {
        res *= x;
    }
    return res;
}

int main() {
//    freopen("input_l.txt","r",stdin);
//    freopen("output.txt","w",stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    for (int i = 0; i < max_n; ++i) {
        c[i][0] = 1;
        for (int j = 1; j <= i; ++j) {
            c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
        }
    }
    cin >> n >> p[0] >> p[1] >> p[2] >> p[3];
    multiset<pair<ld, ll>> q;
    for (int a = 0; a <= n; ++a) {
        for (int b = 0; a + b <= n; ++b) {
            for (int c = 0; a + b + c <= n; ++c) {
                const int d = n - a - b - c;
                ll ways = calc_ways(a, b, c, d);
                ld prob = 1;
                if (a) {
                    prob *= mypow(p[0], a);
                }
                if (b) {
                    prob *= mypow(p[1], b);
                }
                if (c) {
                    prob *= mypow(p[2], c);
                }
                if (d) {
                    prob *= mypow(p[3], d);
                }
//                LOG(a, b, c, d, prob, ways);
                q.insert({prob, ways});
            }
        }
    }
    LOG(q.size());
    ld ans = 0;
    while (!q.empty()) {
        auto [prob, ways] = *q.begin();
//        LOG(prob, ways);
        q.erase(q.begin());
        if (ways >= 2) {
            ans += 2 * prob * (ways / 2);
            q.insert({2 * prob, ways / 2});
            if (ways % 2) {
                q.insert({prob, 1});
            }
        } else {
            if (q.empty()) {
                break;
            }
            auto [prob2, ways2] = *q.begin();
//            LOG(prob2, ways2);
            ans += (prob + prob2);
            q.erase(q.begin());
            q.insert({prob + prob2, 1});
            if (ways2 > 1) {
                q.insert({prob2, ways2 - 1});
            }
        }
    }
    cout << fixed << setprecision(10) << (long double) ans << "\n";
    exit(0);
}