#include <bits/stdc++.h>

using namespace std;

const int MOD = 1000000007;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int N;
  cin >> N;
  vector<int> A(N);
  for (int i = 0; i < N; i++) {
    cin >> A[i];
  }
  for (int k = N - 1; k > -1; k--) {
    for (int i = 0; i < k; i++) {
      A[i] = (A[i] + A[i + 1]) % MOD;
    }
  }
  cout << A[0] << '\n';
  return 0;
}