#include "bits/stdc++.h" using namespace std; // Inserted snippets: io, root #define rep(i, a, b) for(int i = a; i < (b); ++i) #define all(x) begin(x), end(x) #define sz(x) (int)(x).size() typedef long long ll; typedef pair<int, int> pii; typedef vector<int> vi; template<typename H> bool chmin(H& v1, const H v2) { if (v1 > v2) { v1 = v2; return true; } return false; } template<typename H> bool chmax(H& v1, const H v2) { if (v1 < v2) { v1 = v2; return true; } return false; } template<typename H> void read(H& head) { cin >> head; } template<typename H, typename ...T> void read(H& head, T& ...tail) { cin >> head; read(tail...); } template<typename H> void write(H head) { cout << head << '\n'; } template<typename H, typename ...T> void write(H head, T ...tail) { cout << head << " "; write(tail...); } template<typename ...T> void die(T ...tok) { write(tok...); exit(0); } // End snippets int main() { cin.tie(0)->sync_with_stdio(0); cin.exceptions(cin.failbit); int n; read(n); vector<ll> v(n); rep(i, 0, n) cin >> v[i]; while (v.size() > 1) { vector<ll> w(sz(v) - 1); rep(i, 0, sz(w)) w[i] = (v[i] + v[i + 1]) % 1000000007; v = w; } cout << v[0] << endl; }