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

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>

const int MOD = 1e9+7;

int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  rep(i,n) cin >> a[i];
  rep(i,n-1) {
    vector<int> na;
    rep(i,a.size()-1) {
      na.push_back((a[i]+a[i+1])%MOD);
    }
    a = na;
  }
  cout << a[0] << endl;



}