#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
using ll = long long;
#define rep(i, n) for (int i = 0; i < (n); ++i)

int main() {
  int n;
  cin >> n;
  vector<ll> a(n);
  rep(i, n) cin >> a[i];
  constexpr ll MOD = 1e9 + 7;
  rep(_, n - 1) {
    vector<ll> b(a.size() - 1);
    rep(i, b.size()) b[i] = (a[i] + a[i + 1]) % MOD;
    swap(a, b);
    Debug(a);
  }
  cout << a[0] << endl;
  return 0;
}