#include <bits/stdc++.h>

using ll = long long;

using namespace std;

constexpr ll m = pow(10,9) + 7;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    ll a[n]{};

    for (int i=0;i<n;++i)
        cin >> a[i];

    for (int i=n-1;i>0;--i)
    {
        for (int j=0;j<=i;++j)
           a[j]+=a[j+1];
    }

    cout << a[0]%m << "\n";

    return 0;
}