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

long long fac[MAX], finv[MAX], inv[MAX];
//invの要素にはiの逆元が格納されている
//前処理
void COMinit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;//i!(mod MOD)を計算
        inv[i] = MOD - inv[MOD%i]* (MOD / i) % MOD;//iの逆元を計算
        finv[i] = finv[i - 1] * inv[i] % MOD;//i!(mod MOD)の逆元を計算
    }
}

// 二項係数計算
long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;//nCk = n!/(k!*(n-k)!)を計算
}
//例のアレ
long long nPm(int n, int m){
    if(n < m) return 0;
    if(n < 0 || m < 0) return 0;
    return fac[n] * finv[n - m] % MOD;
}
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;
    }
    for(int i = 0; i < N; i++){
        if(A[i] >= 4) flag = 1;
    }
    if(flag == 1){
        cout << -1 << 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;
}