#include <bits/stdc++.h>
using namespace std;
const int inf = (int)1.01e9;
const long long infll = (long long)1.01e18;
const long double eps = 1e-9;
const long double pi = acos((long double)-1);
mt19937 mrand(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x) { return mrand() % x; }
void precalc() {}
const int mod = (int)1e9 + 7;
int mul(int a, int b) { return (long long)a * b % mod; }
void add(int &a, int b) {
  a += b;
  if (a >= mod) {
    a -= mod;
  }
}
pair<int, int> gcd(int a, int b) {
  if (!b) {
    return make_pair(1, 0);
  }
  auto p = gcd(b, a % b);
  return make_pair(p.second, p.first - (a / b) * p.second);
}
int inv(int x) {
  int res = gcd(x, mod).first % mod;
  if (res < 0) {
    res += mod;
  }
  return res;
}
const int maxn = 15, pown = (1 << maxn);
int n;
int a[maxn];
bool read() {
  if (scanf("%d", &n) < 1) {
    return false;
  }
  for (int i = 0; i < n; ++i) {
    scanf("%d", &a[i]);
  }
  return true;
}
int g[maxn][maxn];
int mem[maxn][pown];
int dp[pown];
void solve() {
  for (int i = 0; i < n; ++i) {
    for (int j = i + 1; j < n; ++j) {
      int q = inv(a[i] + a[j]);
      g[i][j] = mul(a[i], q);
      g[j][i] = mul(a[j], q);
    }
  }
  for (int v = 0; v < n; ++v) {
    for (int msk = 0; msk < (1 << n); ++msk) {
      auto &cur = mem[v][msk];
      cur = 1;
      for (int u = 0; u < n; ++u) {
        if (!(msk & (1 << u))) {
          continue;
        }
        cur = mul(cur, g[v][u]);
      }
    }
  }
  for (int msk = 1; msk < (1 << n); ++msk) {
    auto &cur = dp[msk];
    cur = 1;
    for (int sub = ((msk - 1) & msk); sub > 0; sub = ((sub - 1) & msk)) {
      int pr = dp[sub];
      for (int v = 0; v < n; ++v) {
        if (!(sub & (1 << v))) {
          continue;
        }
        pr = mul(pr, mem[v][msk ^ sub]);
      }
      add(cur, mod - pr);
    }
  }
  int res = 0;
  for (int msk = 1; msk < (1 << n); ++msk) {
    auto cur = dp[msk];
    for (int v = 0; v < n; ++v) {
      if (!(msk & (1 << v))) {
        continue;
      }
      cur = mul(cur, mem[v][((1 << n) - 1) ^ msk]);
    }
    add(res, mul(__builtin_popcount(msk), cur));
  }
  printf("%d\n", res);
}
int main() {
  precalc();
  while (read()) {
    solve();
  }
  return 0;
}
