#include <bits/stdc++.h>

#define rep(X,N) for(ll X = 0LL; X < (N); X++)
#define PI (acos(-1.0))
#define MODN 1000000007
#define MODN2 998244353
#define ALL(V) (V).begin(),(V).end()
#define INT_MAX_HALF (INT_MAX / 2)
#define EPS (1e-10)

using namespace std;
typedef long long ll;

void calc(vector<int> &v){
    
    vector<int> result;
    int size = v.size();

    rep(i, size - 1){
        result.push_back((v[i] + v[i + 1]) % MODN);
    }

    v.clear();

    rep(i, size - 1){
        v.push_back(result[i]);
    }
}

int main(){

    int n;
    cin >> n;

    vector<int> a(n);

    rep(i, n){
        cin >> a[i];
    }

    rep(i, n - 1){
        calc(a);
    }

    cout << a[0] << endl;

    return 0;
}