#include <bits/stdc++.h>
using namespace std;
const int64_t MOD = 1000000007;
int64_t A[110][110];

int main()
{
  int64_t N, ans = 0;
  cin >> N;
  for (int i = 0; i < N; i++)
  {
    cin >> A[0][i];
  }
  for (int i = 1; i < N; i++)
  {
    for (int j = 0; j < N; j++)
    {
      A[i][j] = (A[i - 1][j] + A[i - 1][j + 1]) % MOD;
    }
  }
  cout << A[N - 1][0] << endl;
}