#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int MAXN = 15;
int n, a[MAXN], aa[MAXN][MAXN];
int dp[1 << MAXN];
int x[1 << MAXN][MAXN], f[1 << MAXN], g[1 << MAXN];
int cnt[1 << MAXN];
int power(int x, int n) {
  int res = 1;
  while (n) {
    if (n & 1) res = 1LL * res * x % mod;
    n >>= 1;
    x = 1LL * x * x % mod;
  }
  return res;
}
void solve() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", &a[i]);
  for (int i = 0; i < n; i++)
    for (int j = i + 1; j < n; j++) aa[i][j] = power(a[i] + a[j], mod - 2);
  f[0] = 1;
  for (int i = 1; i < 1 << n; i++) {
    cnt[i] = 0;
    x[i][0] = x[i][1] = f[i] = g[i] = 1;
    for (int j = 0; j < n; j++) {
      if (i & (1 << j)) {
        cnt[i]++;
        x[i][1] = 1LL * x[i][1] * a[j] % mod;
        for (int k = j + 1; k < n; k++)
          if (i & (1 << k)) {
            f[i] = 1LL * f[i] * (a[j] + a[k]) % mod;
            g[i] = 1LL * g[i] * aa[j][k] % mod;
          }
      }
    }
    for (int j = 2; j < n; j++) x[i][j] = 1LL * x[i][j - 1] * x[i][1] % mod;
  }
  int ans = 0, all = (1 << n) - 1;
  for (int i = 1; i < 1 << n; i++) {
    int p = 0;
    for (int j = (i - 1) & i; j; j = (j - 1) & i) {
      p = (p + 1LL * dp[j] * x[j][cnt[i] - cnt[j]] % mod * g[i] % mod * f[j] %
                   mod * f[i ^ j] % mod) %
          mod;
    }
    dp[i] = (1 - p + mod) % mod;
    ans = (ans + 1LL * cnt[i] * dp[i] % mod * x[i][cnt[all] - cnt[i]] % mod *
                     g[all] % mod * f[i] % mod * f[all ^ i] % mod) %
          mod;
  }
  printf("%d\n", ans);
}
int main() {
  int T = 1;
  for (int i = 1; i <= T; i++) solve();
  return 0;
}
