#include <bits/stdc++.h>

#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define endl "\n"
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rrep(i, n) for(int i = ((int)(n)-1); i >= 0; i--)
#define all(x) (x).begin(),(x).end()

using namespace std;
using ll = long long;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> P;
 
const int INF = 1e9;
//const ll INF = 1e18;
const double EPS = 1e-10;
const int MOD = 1e9+7;
const double PI = acos(-1.0);

int main()
{
	int n;
	cin >> n;
	ll comb[n+10][n+10] = {};
	for(int i = 0; i < n; i++) cin >> comb[1][i];
	for(int i = 2; i <= n; i++){
		for(int j = 0; j <= n-i; j++){
			comb[i][j] = comb[i-1][j] + comb[i-1][j+1];
			comb[i][j] %= MOD;
			//cout << comb[i][j] << ' ';
		}
		//cout << endl;
	}
	ll ans = 0;
	for(int i = 0; i < n; i++){
		ans += comb[n][i];
		ans %= MOD;
	}
	cout << ans << endl;
	return 0;
}