#include <iostream>
#include <iomanip>
#include <vector>
#include <utility>
#include <map>
#include <algorithm>
#include <queue>
#include <cmath>
#include <numeric>
#include <set>

using namespace std;
struct aaa{aaa(){cin.tie(nullptr); ios::sync_with_stdio(false); cout<<fixed<<setprecision(20);};}aaa;
template <class T>ostream &operator<<(ostream &o,const vector<T>&v){o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}
#define debug(v) {cerr<<"\033[1;36m[debug]\033[m "<<#v<<" : "<<v<<endl;}

using int64 = long long;

const int MOD = 1000000007;
int main() {
    int n;
    cin >> n;
    vector a(n, 0);
    for (int i=0; i<n; i++) cin >> a[i];

    while(a.size() > 1) {
        vector<int> tmp;
        for (int i=1; i<a.size(); i++) {
            tmp.push_back(a[i-1]+a[i]);
            tmp.back() %= MOD;
        }
        a = tmp;
    }

    cout << a.front() << endl;
}