#include <bits/stdc++.h>
using namespace std;
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
//#define int long long
#define ll long long
#define ull unsigned long long
#define ld long double
#define vl vector<long long>
#define vvl vector<vector<long long>>
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
#define rep2(i, s, n) for (ll i = (s); i < (ll)(n); i++)
#define drep(i, x) for (ll i = ((ll)(x)-1); i >= 0; i--)
#define pll pair<long long,long long>
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define vvc vector<vector<char>>
#define vc vector<char>
#define vvb vector<vector<bool>>
#define vb vector<bool>
#define Maxe(x) *max_element(all(x))
#define Mine(x) *min_element(all(x))
#define Size(x) ((ll)(x).size())
#define umap unordered_map
const long long INF = 1LL << 60;
const long double pi = 3.1415926535897932;
#define Fi first
#define Se second
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

    template<class T> inline bool chmin(T& a, T b) {
        if (a > b) {
            a = b;
            return true;
        }
        return false;
    }
    template<class T> inline bool chmax(T& a, T b) {
        if (a < b) {
            a = b;
            return true;
        }
        return false;
    }

//lis,modpow,uf,modncr,soinsubunkai,yakusurekkyo
//mint,dijkstra,gyakugen

    signed main(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
        ll n;
        cin>>n;
        const int MOD=1000000007;
        vl A(n);
        rep(i,n)cin>>A[i];
        rep(i,n-1){
            rep(j,n-i-1){
                A[j]=A[j]+A[j+1];
                A[j]%=MOD;
            }
        }
        cout<<A[0]<<endl;
    }