#include <bits/stdc++.h>
using namespace std;
long long mmod(long long x, long long y) {
  if (x >= 0LL)
    return x % y;
  else
    return (y - (-x) % y) % y;
}
long long ddiv(long long x, long long y) {
  x -= mmod(x, y);
  return x / y;
}
long long binpow(long long a, long long b, long long mod) {
  if (a == 0) {
    return 0;
  }
  long long pows[65];
  pows[0] = a;
  for (int i = 1; i < 65; ++i) {
    pows[i] = mmod(pows[i - 1] * pows[i - 1], mod);
  }
  long long ans = 1;
  for (int i = 0; b != 0; b >>= 1, ++i) {
    if (b % 2 == 1) {
      ans = mmod(ans * pows[i], mod);
    }
  }
  return ans;
}
long long GCD(long long a, long long b) {
  while (a != 0) {
    b = b % a;
    swap(a, b);
  }
  return b;
}
const int M = 1000000007;
int bmRange;
vector<int> a;
struct frac {
  long long num;
  long long denom;
  frac() : num(0), denom(1) {}
  frac(long long n, long long d) : num(n), denom(d) {}
  frac operator*(const frac& other) const {
    return {mmod(num * other.num, M), mmod(denom * other.denom, M)};
  }
  frac operator+(const frac& other) const {
    return {mmod(num * other.denom + denom * other.num, M),
            mmod(denom * other.denom, M)};
  }
  frac operator-() const { return {mmod(denom - num, M), denom}; }
  long long get() const { return mmod(num * binpow(denom, M - 2, M), M); }
};
vector<frac> probs;
frac get_prob(int submask, int bitmask) {
  frac res(1, 1);
  for (int i = 0; i < 14; ++i)
    for (int j = 0; j < 14; ++j) {
      if ((submask >> i) & 1 && (bitmask >> j) & 1 && !((submask >> j) & 1)) {
        res = res * frac(a[i], a[i] + a[j]);
      }
    }
  return res;
}
frac res{0, 1};
void apply(int bitmask) {
  for (int submask = bitmask & (bitmask - 1); submask != 0;
       submask = bitmask & (submask - 1)) {
    probs[bitmask] =
        probs[bitmask] + (-probs[submask]) * get_prob(submask, bitmask);
  }
  int memc = 0;
  for (int i = 0; i < 14; ++i) {
    if ((bitmask >> i) & 1) ++memc;
  }
  res =
      res + (-probs[bitmask]) * get_prob(bitmask, bmRange - 1) * frac(memc, 1);
}
void solve() {
  int n;
  cin >> n;
  bmRange = (1 << n);
  a.resize(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  probs.resize(bmRange, {0, 1});
  for (int i = 0; i < bmRange; ++i) apply(i);
  cout << res.get() << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int t = 1;
  for (int k = 0; k < t; ++k) solve();
  return 0;
}
