#include <bits/stdc++.h>
using namespace std;

int main() {
  int N;
  cin >> N;
  vector<int> A(N);
  for (int &a : A) cin >> a;
  reverse(A.begin(), A.end());

  while((int)A.size() != 1) {
    for (int i = 0; i < (int)A.size() - 1; i++) {
      A.at(i) += A.at(i + 1);
      A.at(i) %= 1000000007;
    }
    A.pop_back();
  }

  cout << A.at(0) << endl;
}