#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <array>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
using namespace std;

using ll = long long;
using P = pair<int, int>;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
// constexpr int mod = 998244353;

template<class T>
inline bool chmax(T& x, T y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T& x, T y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;
    vector<int> a(n);
    bool zero = false;
    for(int i = 0; i < n; ++i){
        cin >> a[i];
        zero |= a[i] == 0;
    }
    if(zero){
        cout << -1 << endl;
        return 0;
    }

    vector<ll> fact(11, 1);
    for(int i = 1; i <= 10; ++i) fact[i] = fact[i - 1] * i;

    constexpr ll MOD = mod;
    ll prod = 1;
    for(int i = 0; i < n; ++i){
        if(a[i] == 1)   continue;
        if(a[i] > 10){
            prod = MOD + 1;
            break;
        }
        for(int j = 0; j < fact[a[i]]; ++j){
            prod *= a[i];
            if(prod > MOD){
                prod = MOD + 1;
                break;
            }
        }
        if(prod == MOD + 1) break;
    }
    cout << MOD % prod << endl;

    return 0;
}