#include <bits/stdc++.h>
#define int long long
#define vi vector<int>
#define debug(x) cout << #x << " = " << x << "\n";
#define vdebug(a) cout << #a << " = "; for(auto x: a) cout << x << " "; cout << "\n";
#define fi first
#define sc second
using namespace std;


void solve() {

	
	int n;
	cin >> n;

	
	

	vector<pair<int,int>> a(n);

	for(int i = 0; i < n; i++) {
		cin >> a[i].first;
		a[i].second = i; 
	}

	if(n == 1) {
		cout << a[0].first << endl;
		return;
	}
	
	if(n <= 2) {
		cout << max(a[0].first, a[1].first) << endl; return;
	} 

	

	sort(a.begin(), a.end(), greater<pair<int,int>>());

	if(abs(a[0].second - a[1].second) <= 1) {
		cout << a[0].first + a[2].first << endl;
		return;
	} else {
		cout << a[0].first + a[1].first << endl;
		return;
	}

	
}
 
signed main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

    int t = 1;
    //cin >> t;
 

    while (t--) {
        solve();
    }
}