#include <bits/stdc++.h>
using namespace std;
const int N = 15;
const int maxn = 2e5 + 10;
const int mod = 1e9 + 7;
inline int read() {
  int x = 0, f = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    x = (x << 1) + (x << 3) + c - '0';
    c = getchar();
  }
  return x * f;
}
int n, a[N], all, ans, f[1 << N], g[1 << N], iv[N][N], cnt[1 << N], lg[1 << N],
    lw[1 << N];
inline int ksm(int x, int y) {
  int res = 1;
  while (y) {
    if (y & 1) res = 1ll * res * x % mod;
    x = 1ll * x * x % mod;
    y >>= 1;
  }
  return res;
}
inline int lwb(int x) { return x & (-x); }
inline void add(int &x, int y) { x = (x + y >= mod ? x + y - mod : x + y); }
inline void sub(int &x, int y) { x = (x < y ? x - y + mod : x - y); }
int main() {
  n = read();
  all = (1 << n) - 1;
  for (int i = 0; i < n; i++) a[i] = read();
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) iv[i][j] = ksm(a[i] + a[j], mod - 2);
  for (int i = 1; i <= all; i++) {
    g[i] = 1;
    for (int j = 0; j < n; j++)
      if (i >> j & 1)
        for (int k = 0; k < n; k++)
          if (~i >> k & 1) g[i] = 1ll * g[i] * a[j] % mod * iv[j][k] % mod;
  }
  lg[0] = -1;
  for (int i = 1; i <= all; i++) {
    cnt[i] = cnt[i >> 1] + (i & 1);
    lg[i] = lg[i >> 1] + 1;
    lw[i] = lwb(i);
    lw[i] = lg[lw[i]];
  }
  for (int i = 1; i <= all; i++) {
    f[i] = g[i];
    for (int s = ((i - 1) & i); s; s = ((s - 1) & i)) {
      int cur = 1;
      for (int j = s; j; j &= (j - 1))
        for (int k = (i ^ s); k; k &= (k - 1))
          cur = 1ll * cur * a[lw[k]] % mod * iv[lw[j]][lw[k]] % mod;
      sub(f[i], 1ll * f[s] * g[i ^ s] % mod * ksm(cur, mod - 2) % mod);
    }
    add(ans, 1ll * cnt[i] * f[i] % mod);
  }
  printf("%d\n", ans);
  return 0;
}
