#include <bits/stdc++.h>
using namespace std;
long long int a[16];
long long int dp[1000000];
long long int cost[16][16];
long long int modpow(long long int base, int exp) {
  if (exp == 0) return 1;
  if (exp == 1) return base;
  long long int pv = modpow(base, exp / 2);
  pv = (pv * pv) % int(1e9 + 7);
  if (exp % 2 == 0) return pv;
  pv = (base * pv) % int(1e9 + 7);
  return pv;
}
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      cost[i][j] =
          (a[i] * modpow(a[i] + a[j], int(1e9 + 7) - 2)) % int(1e9 + 7);
    }
  }
  for (int msk = 1; msk < (1 << n); msk++) {
    if (__builtin_popcount(msk) == 1) {
      dp[msk] = 1;
      continue;
    }
    vector<int> v;
    v.clear();
    for (int i = 0; i < n; i++) {
      int x = msk & (1 << i);
      if (x > 0) v.push_back(i);
    }
    int sz = v.size();
    dp[msk] = 1;
    for (int submask = 1; submask < (1 << sz) - 1; submask++) {
      long long int naive = 1;
      int prev_mask = 0;
      vector<int> inside_bits, outside_bits;
      inside_bits.clear();
      outside_bits.clear();
      for (int i = 0; i < sz; i++) {
        int x = submask & (1 << i);
        if (x > 0) {
          inside_bits.push_back(v[i]);
          prev_mask += (1 << v[i]);
        } else
          outside_bits.push_back(v[i]);
      }
      assert(!inside_bits.empty());
      assert(!outside_bits.empty());
      for (int in : inside_bits) {
        for (int out : outside_bits) {
          naive = naive * cost[in][out] % int(1e9 + 7);
        }
      }
      assert(prev_mask < (1 << n));
      dp[msk] -= (dp[prev_mask] * naive) % int(1e9 + 7);
      dp[msk] %= int(1e9 + 7);
    }
  }
  long long int ret = 0;
  for (int msk = 1; msk < (1 << n); msk++) {
    long long int naive = 1;
    for (int t = 0; t < n; t++) {
      for (int q = 0; q < n; q++) {
        int x = msk & (1 << t);
        int y = msk & (1 << q);
        if (x > 0 and y == 0) naive = (naive * cost[t][q]) % int(1e9 + 7);
      }
    }
    ret = (ret + (((__builtin_popcount(msk) * naive) % int(1e9 + 7)) * dp[msk] %
                  int(1e9 + 7))) %
          int(1e9 + 7);
  }
  if (ret < 0) ret += int(1e9 + 7);
  cout << ret << endl;
}
