#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define PI acos(-1)
const int mod = 1e9+7;
ll bigMod(ll a,ll b)
{
    ll ans=1;
    while(b)
    {
        if(b&1) ans = (ans*a);
        a = (a*a);
        b >>=1;
    }
    return ans;
}
int main()
{
    int n;
    cin >> n;
    vector<ll>arr(n);
    for(int i=0; i<n; i++)
    {
        cin >> arr[i];
    }
    sort(arr.begin(),arr.end());
    ll answer = 1;
    ll mn = arr[0];
    ll mx = arr[n-1];
    if(mn == 0) answer = -1;
    else if(mx >=4 )answer = mod;
    else
    {
        ll ans = 1;
        for(ll x : arr)
        {
            if(x==1)ans = (ans * 1);
            else if(x==2)ans = (ans * 4);
            else if(x==3)ans = (ans * 729);
            answer = mod % ans;
            if(ans>mod)
            {
                break;
            }
        }
    }
    cout << answer << endl;
}