#include <bits/stdc++.h>

using namespace std;

int factorial(int x) {
  int res = 1;
  for (int i = 1; i < x + 1; i++) {
    res *= i;
  }
  return res;
}

template <typename T>
int64_t pow(int64_t x, T n, int64_t mod = std::numeric_limits<int64_t>::max()) {
  int64_t res = 1;
  while (n > 0) {
    if (n & 1) res = static_cast<__int128>(res) * static_cast<__int128>(x) % mod;
    x = static_cast<__int128>(x) * static_cast<__int128>(x) % mod;
    n >>= 1;
  }
  return res;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  const int MOD = 1000000007;
  int N;
  cin >> N;
  vector<int64_t> A(N);
  for (auto&& e : A) {
    cin >> e;
    if (e == 0) {
      cout << -1 << '\n';
      return 0;
    }
  }
  int64_t res = 1;
  for (int i = 0; i < N; i++) {
    int64_t a = A[i];
    if (a > 3) {
      cout << MOD << '\n';
      return 0;
    }
    res *= pow(a, factorial(a));
    if (res > MOD) {
      cout << MOD << '\n';
      return 0;
    }
  }
  cout << MOD % res << '\n';
  return 0;
}