#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
#define rep(i,n) for(ll i=0;i<(n);i++)
#define pll pair<ll,ll>
#define pii pair<int,int>
#define pq priority_queue
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define endl '\n'
#define ios ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define lb(c,x) distance(c.begin(),lower_bound(all(c),x))
#define ub(c,x) distance(c.begin(),upper_bound(all(c),x))

using namespace std;

const ll mod=1e9+7;

int main(){
    ll n;
    cin >> n;
    vector<ll> a(n);
    bool zero=false;
    bool over=false;
    rep(i,n){
        cin >> a[i];
        if(a[i]==0) zero=true;
    }
    if(zero){
        cout << -1 << endl;
    }
    ll val=1;
    rep(i,n){
        if(over) break;
        for(ll j=1;j<=a[i];j++){
            rep(k,j){
                val*=a[i];
                if(val>mod) break;
            }
            if(val>mod) break;
        }
        if(val>mod) break;
    }
    if(val>mod) over=true;
    if(over) cout << mod << endl;
    else cout << mod%val << endl;
    return 0;
}