#include <iostream>
#include <vector>
using namespace std;
const int MAX = 410000;
const int MOD = 1000000007;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    cin >> N;
    vector<long long> A(N);
    for(int i = 0; i < N; i++) cin >> A[i];
    int flag = 0;
    for(int i = 0; i < N; i++){
        if(A[i] == 0) flag = 1;
    }
    if(flag == 1){
        cout << -1 << endl;
        return 0;
    }
    for(int i = 0; i < N; i++){
        if(A[i] >= 4) flag = 1;
    }
    if(flag == 1){
        cout << MOD << endl;
        return 0;
    }
    vector<long long> kai(4);
    for(int i = 0; i < 4; i++){
        if(i == 0) kai[i] = 1;
        else kai[i] = kai[i - 1] * i;
    }
    long long temp = 1;
    for(int i = 0; i < N; i++){
        long long res = 1;
        long long cnt = kai[A[i]];
        long long x = A[i];
        while(cnt > 0){
            if(cnt & 1) res *= x;
            x = x * x;
            cnt >>= 1;
        }
        temp *= res;
        if(temp > MOD){
            cout << MOD << endl;
            return 0;
        }
    }
    cout << MOD % temp << endl;
}