//#include <atcoder/all>
//using namespace atcoder;
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n) for(int i=0; i<n; i++)
#define REPR(i, n) for(int i=n-1; i>=0; i--)
#define FOR(i, m, n) for(int i=m; i<n; i++)
#define ALL(v) v.begin(), v.end()
#define SIZE(x) int(x.size()) 
#define bit(n) (1LL<<(n))
#define FIX(d) fixed << setprecision(d)
using P = pair<int, int>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<ll>>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = 1e9;
const ll LINF = (1LL<<60);

const ll m = 1e9+7;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n; cin >> n;
  vector<ll> a(n);
  REP(i,n) cin >> a[i];

  if(*min_element(ALL(a))==0){
    cout << -1 << endl;
    return 0;
  }
  if(*max_element(ALL(a))>=4){
    cout << 1e9+7 << endl;
    return 0;
  }

  ll ans = 1;
  REP(i,n){
    ll kai = 1;
    FOR(j,1,a[i]+1) kai *= j;
    ans *= ll(pow(a[i],kai));
    if(ans>m) break;
  }
  cout << m%ans << endl;
  return 0;
}