#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
const int inf = (1 << 30) - 1;
const ll INF = (1LL << 60) - 1;
template <typename T>
bool chmax(T &x, const T &y) {
  return (x < y) ? (x = y, true) : false;
};
template <typename T>
bool chmin(T &x, const T &y) {
  return (x > y) ? (x = y, true) : false;
};
struct io_setup {
  io_setup() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout << fixed << setprecision(15);
  }
} io_setup;
template <int mod>
struct Mod_Int {
  int x;
  Mod_Int() : x(0) {}
  Mod_Int(long long y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
  static int get_mod() { return mod; }
  Mod_Int &operator+=(const Mod_Int &p) {
    if ((x += p.x) >= mod) x -= mod;
    return *this;
  }
  Mod_Int &operator-=(const Mod_Int &p) {
    if ((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }
  Mod_Int &operator*=(const Mod_Int &p) {
    x = (int)(1LL * x * p.x % mod);
    return *this;
  }
  Mod_Int &operator/=(const Mod_Int &p) {
    *this *= p.inverse();
    return *this;
  }
  Mod_Int &operator++() { return *this += Mod_Int(1); }
  Mod_Int operator++(int) {
    Mod_Int tmp = *this;
    ++*this;
    return tmp;
  }
  Mod_Int &operator--() { return *this -= Mod_Int(1); }
  Mod_Int operator--(int) {
    Mod_Int tmp = *this;
    --*this;
    return tmp;
  }
  Mod_Int operator-() const { return Mod_Int(-x); }
  Mod_Int operator+(const Mod_Int &p) const { return Mod_Int(*this) += p; }
  Mod_Int operator-(const Mod_Int &p) const { return Mod_Int(*this) -= p; }
  Mod_Int operator*(const Mod_Int &p) const { return Mod_Int(*this) *= p; }
  Mod_Int operator/(const Mod_Int &p) const { return Mod_Int(*this) /= p; }
  bool operator==(const Mod_Int &p) const { return x == p.x; }
  bool operator!=(const Mod_Int &p) const { return x != p.x; }
  Mod_Int inverse() const {
    assert(*this != Mod_Int(0));
    return pow(mod - 2);
  }
  Mod_Int pow(long long k) const {
    Mod_Int now = *this, ret = 1;
    for (; k > 0; k >>= 1, now *= now) {
      if (k & 1) ret *= now;
    }
    return ret;
  }
  friend ostream &operator<<(ostream &os, const Mod_Int &p) {
    return os << p.x;
  }
  friend istream &operator>>(istream &is, Mod_Int &p) {
    long long a;
    is >> a;
    p = Mod_Int<mod>(a);
    return is;
  }
};
using mint = Mod_Int<MOD>;
int main() {
  int N;
  cin >> N;
  vector<mint> a(N);
  for (int i = 0; i < N; i++) cin >> a[i];
  vector<vector<mint>> iv(N, vector<mint>(N));
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < N; j++) {
      iv[i][j] = (a[i] + a[j]).inverse();
    }
  }
  vector<vector<mint>> dp1(N, vector<mint>(1 << N, 1));
  for (int i = 0; i < N; i++) {
    for (int j = 0; j < 1 << N; j++) {
      for (int k = 0; k < N; k++) {
        if ((j >> k) & 1) {
          dp1[i][j] *= a[i] * iv[i][k];
        }
      }
    }
  }
  vector<mint> dp(1 << N, 1);
  for (int i = 0; i < 1 << N; i++) {
    for (int j = i; j > 0; j--, j &= i) {
      if (j == i) continue;
      mint tmp = 1;
      for (int k = 0; k < N; k++) {
        if ((j >> k) & 1) {
          tmp *= dp1[k][i & ~j];
        }
      }
      dp[i] -= dp[j] * tmp;
    }
  }
  mint ans = 0;
  for (int i = 0; i < 1 << N; i++) {
    if (i == 0) continue;
    int j = ((1 << N) - 1) ^ i;
    for (int k = 0; k < N; k++) {
      if ((i >> k) & 1) dp[i] *= dp1[k][j];
    }
    ans += dp[i] * __builtin_popcount(i);
  }
  cout << ans << '\n';
}
