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

int main() {
  int N;
  cin >> N;
  vector<long long> A(N);
  for (int i = 0; i < N; ++i) {
    cin >> A[i];
  }

  for (int i = 0; i < N - 1; ++i) {
    vector<long long> A2(A.size() - 1);
    for (size_t j = 0; j < A.size() - 1; ++j) {
      A2[j] = (A[j + 1] + A[j]) % 1000000007;
    }
    A = A2;
  }

  cout << A[0] << endl;
}