#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
//using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using i128 = __int128_t;
using u128 = unsigned __int128_t;
using mint = atcoder::static_modint<1000000007>;
const int mod = 1000000007;
#include <chrono>
mt19937_64 rng(std::chrono::steady_clock::now().time_since_epoch().count());
int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1};
int dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};
template<class T>
bool chmin(T& a, const T& b){
    if (b < a){
        a = b;
        return true;
    }
    else { 
        return false;
    }
}
template<class T> 
bool chmax(T& a, const T& b){
    if (a < b){
        a = b;
        return true;
    }
    else {
        return false;
    }
}

void solve(){
    int n;
    cin >> n;
    vector<int> a(n);
    bool ok = true;
    for (int i = 0; i < n; i++){
        cin >> a[i];
        if (a[i] == 0){
            ok = false;
        }
    }
    if (!ok){
        cout << -1 << '\n';
        return;
    }
    ll now = 1;
    for (int i = 0; i < n; i++){
        if (a[i] == 1){
            continue;
        }
        if (a[i] >= 4){
            cout << mod << '\n';
            return;
        }
        if (a[i] == 2){
            for (int j = 0; j < 2; j++){
                now *= a[i];
                if (now > mod){
                    cout << mod << '\n';
                    return;
                }                
            }
        }
        else {
            for (int j = 0; j < 6; j++){
                now *= a[i];
                if (now > mod){
                    cout << mod << '\n';
                    return;
                }                
            }
        }
    }
    cout << mod % now << '\n';
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;   
    while(t--){
        cout << fixed << setprecision(15);          
        solve();
    }   
}