#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using Modint = atcoder::modint1000000007;

int main(){
    int N;
    cin >> N;
    vector<int> A(N);
    for(int& a : A) cin >> a;
    Modint ans = 0, c = 1;
    for(int a : A){
        ans *= 3;
        c *= Modint::raw(a);
        ans += c;
    }
    ans -= c;
    ans *= Modint::raw(2) / Modint::raw(3);
    ans += c;
    cout << ans.val() << endl;
}