#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18;
const int inf = 1e9;
#define rep(i, a, b) for (int i = a; i < b; i++)
#define per(i, b, a) for (int i = a - 1; i >= b; i--)
using Graph = vector<vector<int>>;
using pint = pair<int, int>;
int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int dxx[8] = {1, 1, 1, 0, 0, -1, -1, -1}, dyy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};

int main() {
    int n;
    cin >> n;
    ll a[n];
    rep (i, 0, n) { cin >> a[i]; }
    ll sum = 0;
    ll mod = 1e9 + 7;
    rep (i, 0, n - 1) {
        rep (j, 0, n - i - 1) { a[j] = (a[j] + a[j + 1]) % mod; }
    }
    cout << a[0] << "\n";
}