#include<bits/stdc++.h>
using namespace std;
using ll = long long;
ll mod = 1000000007;
int main() {
    int N;
    cin >> N;
    vector<ll>A(N);
    for(int i = 0; i < N; i++) cin >> A[i];
    for(int i = 1; i < N; i++) 
        for(int j = i; j < N-i+1; j++) {
            A[j-1] = A[j-1]+A[j];
            A[j-1] %= mod;
        }
    cout << A[0] << endl;
}