#define LOCAL
#include <bits/stdc++.h>
using namespace std;
#pragma region Macros
typedef long long ll;
typedef __int128_t i128;
typedef unsigned int uint;
typedef unsigned long long ull;
#define ALL(x) (x).begin(), (x).end()

template <typename T> istream& operator>>(istream& is, vector<T>& v) {
    for (T& x : v) is >> x;
    return is;
}
template <typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
    for (size_t i = 0; i < v.size(); i++) {
        os << v[i] << (i + 1 == v.size() ? "" : " ");
    }
    return os;
}
template <typename T, typename U> ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << '(' << p.first << ',' << p.second << ')';
    return os;
}
template <typename T, typename U> ostream& operator<<(ostream& os, const map<T, U>& m) {
    os << '{';
    for (auto itr = m.begin(); itr != m.end();) {
        os << '(' << itr->first << ',' << itr->second << ')';
        if (++itr != m.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T, typename U> ostream& operator<<(ostream& os, const unordered_map<T, U>& m) {
    os << '{';
    for (auto itr = m.begin(); itr != m.end();) {
        os << '(' << itr->first << ',' << itr->second << ')';
        if (++itr != m.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const set<T>& s) {
    os << '{';
    for (auto itr = s.begin(); itr != s.end();) {
        os << *itr;
        if (++itr != s.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const multiset<T>& s) {
    os << '{';
    for (auto itr = s.begin(); itr != s.end();) {
        os << *itr;
        if (++itr != s.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const unordered_set<T>& s) {
    os << '{';
    for (auto itr = s.begin(); itr != s.end();) {
        os << *itr;
        if (++itr != s.end()) os << ',';
    }
    os << '}';
    return os;
}
template <typename T> ostream& operator<<(ostream& os, const deque<T>& v) {
    for (size_t i = 0; i < v.size(); i++) {
        os << v[i] << (i + 1 == v.size() ? "" : " ");
    }
    return os;
}
template <typename T, size_t N> ostream& operator<<(ostream& os, const array<T, N>& v) {
    for (size_t i = 0; i < N; i++) {
        os << v[i] << (i + 1 == N ? "" : " ");
    }
    return os;
}

template <int i, typename T> void print_tuple(ostream&, const T&) {}
template <int i, typename T, typename H, class... Args> void print_tuple(ostream& os, const T& t) {
    if (i) os << ',';
    os << get<i>(t);
    print_tuple<i + 1, T, Args...>(os, t);
}
template <typename... Args> ostream& operator<<(ostream& os, const tuple<Args...>& t) {
    os << '{';
    print_tuple<0, tuple<Args...>, Args...>(os, t);
    return os << '}';
}

void debug_out() { cerr << '\n'; }
template <class Head, class... Tail> void debug_out(Head&& head, Tail&&... tail) {
    cerr << head;
    if (sizeof...(Tail) > 0) cerr << ", ";
    debug_out(move(tail)...);
}
#ifdef LOCAL
#define debug(...)                                                                   \
    cerr << " ";                                                                     \
    cerr << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]" << '\n'; \
    cerr << " ";                                                                     \
    debug_out(__VA_ARGS__)
#else
#define debug(...) void(0)
#endif

template <typename T> T gcd(T x, T y) { return y != 0 ? gcd(y, x % y) : x; }
template <typename T> T lcm(T x, T y) { return x / gcd(x, y) * y; }

int topbit(signed t) { return t == 0 ? -1 : 31 - __builtin_clz(t); }
int topbit(long long t) { return t == 0 ? -1 : 63 - __builtin_clzll(t); }
int botbit(signed a) { return a == 0 ? 32 : __builtin_ctz(a); }
int botbit(long long a) { return a == 0 ? 64 : __builtin_ctzll(a); }
int popcount(signed t) { return __builtin_popcount(t); }
int popcount(long long t) { return __builtin_popcountll(t); }
bool ispow2(int i) { return i && (i & -i) == i; }
long long MSK(int n) { return (1LL << n) - 1; }

template <class T> T ceil(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? (x + y - 1) / y : x / y);
}
template <class T> T floor(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? x / y : (x - y + 1) / y);
}

template <class T1, class T2> inline bool chmin(T1& a, T2 b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template <class T1, class T2> inline bool chmax(T1& a, T2 b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template <typename T> void mkuni(vector<T>& v) {
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
}
template <typename T> int lwb(const vector<T>& v, const T& x) { return lower_bound(v.begin(), v.end(), x) - v.begin(); }
#pragma endregion

#include <iostream>

template <typename T> class Rational {
public:
    T num, den;

    static T my_gcd(T x_, T y_) {
        unsigned long long x = x_ < 0 ? -x_ : x_, y = y_ < 0 ? -y_ : y_;
        if (!x or !y) return x + y;
        int n = __builtin_ctzll(x), m = __builtin_ctzll(y);
        x >>= n, y >>= m;
        while (x != y) {
            if (x > y)
                x = (x - y) >> __builtin_ctzll(x - y);
            else
                y = (y - x) >> __builtin_ctzll(y - x);
        }
        return x << (n > m ? m : n);
    }

    void normalize() {
        T g = my_gcd(num, den);
        num /= g, den /= g;
        if (den < 0) num = -num, den = -den;
    }

    Rational() {}
    Rational(T num) : num(num), den(T(1)) {}
    Rational(T num, T den) : num(num), den(den) { normalize(); }

    Rational operator+(const Rational& r) const { return Rational(num * r.den + den * r.num, den * r.den); }
    Rational operator-(const Rational& r) const { return Rational(num * r.den - den * r.num, den * r.den); }
    Rational operator*(const Rational& r) const { return Rational(num * r.num, den * r.den); }
    Rational operator/(const Rational& r) const { return Rational(num * r.den, den * r.num); }
    Rational& operator+=(const Rational& r) { return *this = *this + r; }
    Rational& operator-=(const Rational& r) { return *this = *this - r; }
    Rational& operator*=(const Rational& r) { return *this = *this * r; }
    Rational& operator/=(const Rational& r) { return *this = *this / r; }

    Rational operator+(const T& val) const { return *this + Rational(val); }
    Rational operator-(const T& val) const { return *this - Rational(val); }
    Rational operator*(const T& val) const { return *this * Rational(val); }
    Rational operator/(const T& val) const { return *this / Rational(val); }
    Rational& operator+=(const T& val) { return *this = *this + val; }
    Rational& operator-=(const T& val) { return *this = *this - val; }
    Rational& operator*=(const T& val) { return *this = *this * val; }
    Rational& operator/=(const T& val) { return *this = *this / val; }
    friend Rational operator+(const T& val, const Rational& r) { return r + val; }
    friend Rational operator-(const T& val, const Rational& r) { return r - val; }
    friend Rational operator*(const T& val, const Rational& r) { return r * val; }
    friend Rational operator/(const T& val, const Rational& r) { return r / val; }

    Rational operator-() const { return Rational(-num, den); }
    Rational abs() const { return Rational(num < 0 ? -num : num, den); }

    bool operator==(const Rational& r) const {
        if (den == 0 and r.den == 0) return num == r.num;
        if (den == 0 or r.den == 0) return false;
        return num * r.den == den * r.num;
    }
    bool operator!=(const Rational& r) const { return !(*this == r); }
    bool operator<(const Rational& r) const {
        if (den == 0 and r.den == 0) return num < r.num;
        if (den == 0) return num < 0;
        if (r.den == 0) return r.num > 0;
        return num * r.den < den * r.num;
    }
    bool operator<=(const Rational& r) const { return (*this == r) or (*this < r); }
    bool operator>(const Rational& r) const { return r < *this; }
    bool operator>=(const Rational& r) const { return (*this == r) or (*this > r); }

    bool operator==(const T& val) const { return *this == Rational(val); }
    bool operator!=(const T& val) const { return *this != Rational(val); }
    bool operator<(const T& val) const { return *this < Rational(val); }
    bool operator<=(const T& val) const { return *this <= Rational(val); }
    bool operator>(const T& val) const { return *this > Rational(val); }
    bool operator>=(const T& val) const { return *this >= Rational(val); }
    friend bool operator==(const T& val, const Rational& r) { return r == val; }
    friend bool operator!=(const T& val, const Rational& r) { return r != val; }
    friend bool operator<(const T& val, const Rational& r) { return r > val; }
    friend bool operator<=(const T& val, const Rational& r) { return r >= val; }
    friend bool operator>(const T& val, const Rational& r) { return r < val; }
    friend bool operator>=(const T& val, const Rational& r) { return r <= val; }

    explicit operator double() const { return (double)num / (double)den; }
    explicit operator long double() const { return (long double)num / (long double)den; }
    friend std::ostream& operator<<(std::ostream& os, const Rational& r) { return os << r.num << '/' << r.den; }
};

const int INF = 1e9;
const long long IINF = 1e18;
const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
const char dir[4] = {'D', 'R', 'U', 'L'};
const long long MOD = 1000000007;
// const long long MOD = 998244353;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<int> A(N);
    cin >> A;

    vector<Rational<ll>> dp(1 << N, 0);
    dp[0] = 1;
    for (int mask = 0; mask < (1 << N); mask++) {
        int Max = 0, cnt = 0;
        for (int i = 0; i < N; i++) {
            if (mask >> i & 1)
                chmax(Max, A[i]);
            else
                cnt++;
        }
        for (int i = 0; i < N; i++) {
            if (mask >> i & 1) continue;
            if (A[i] < Max) continue;
            dp[mask | 1 << i] += dp[mask] / cnt;
        }
    }

    auto ans = dp.back();
    assert(ans.num == 1);
    cout << ans.den << '\n';
    return 0;
}