#include <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long ll;

#define MOD 1000000007

int main() {
  int n;
  cin >> n;
  vector<ll> a(n);
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
  }
  for (int t = 0; t < n - 1; ++t) {
    for (int i = 0; i + 1 < n; ++i) {
      a[i] = a[i] + a[i + 1];
      a[i] %= MOD;
    }
  }
  cout << a[0] << endl;
  return 0;
}