#include<bits/stdc++.h>
#include<random>
using namespace std;
#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
//#define vec vector<ll>
//#define mat vector<vector<ll> >
#define fi first
#define se second
#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=INF;
const ll MAX=100010;
const double PI=acos(-1.0);
typedef vector<vector<ll> > mat;
typedef vector<ll> vec;


void solve(){
    ll ans=0;
    ll n;cin>>n;
    ll now=1;
    vector<ll>a(n);
    rep(i,n){
        cin>>a[i];
    }
    REP(i,1,n){
        a[i]=a[i-1]*a[i]%mod;
    }
    for(int i=n-1;i>=0;i--){
        if(i==n-1)ans=(ans+now*a[i])%mod;
        else{
            ans=(ans+now*2LL%mod*a[i])%mod;
            now=now*3%mod;
        }
    }
    cout<<ans<<endl;
}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    solve();
}