#include<iostream>
#include<map>
#include<vector>
#include <algorithm>
#include<math.h>
#include <iomanip>
#include<set>
#include <numeric>
using namespace std;


int main()
{
    long long n, mod = 1e9+7;
    cin >> n;
    vector<long long> v(n);
    for (int i = 0; i < n; i++) cin >> v[i];
    for (int i = 0; i < n-1; i++){
        for (int j = 0; j < n-i -1; j++){
            v[j] = v[j] + v[j+1];
            v[j] %= mod;
        }
    }
    cout << v[0] << endl;
}