#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1000000007;
const long long INF = 1LL << 60;
#define rep(i,n) for(int i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()

int main() {
    ll n, num = 2, ans = 0, anss;
    cin >> n >> anss;
    rep(i,n-2) num = num*3%MOD;
    anss %= MOD;
    ans += anss*num%MOD;
    rep(i,n-1){
        num = (num+num%3*MOD)/3;
        if(i == n-2) num = 1;
        ll a;
        cin >> a;
        anss = anss*a%MOD;
        ans = anss*num%MOD;
    }
    cout << ans << endl;
}