#include <bits/stdc++.h>
#define ll long long
#define pb push_back

using namespace std;

int main()
{
    ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);

	int n;
	cin >> n;

	vector<int> a(n);
	for(int i=0; i<n; i++) cin >> a[i];
	sort(a.begin(), a.end());

	int M = 0;
	priority_queue<pair<int, int>> pq;
	set<int> S;
	int ans = -1;
	for(int i=6; i<n; i++)
    {
        pq.push({a[i-2] - a[i-3] - a[i-4] - a[i-5] - a[i-6], i - 2});
        S.insert(i - 2);

        while(!pq.empty() && pq.top().first >= - a[i-1])
        {
            S.erase(pq.top().second);
            pq.pop();
        }

        if(S.empty()) continue;

        int l1 = *S.rbegin();

        int l0 = i, r0 = n - 1;
        while(l0 != r0)
        {
            int m = (l0 + r0 + 1)/2;

            if(a[m] >= a[i-1] + a[l1]) r0 = m - 1;
            else l0 = m;
        }

        if(a[l0] >= a[i-1] + a[l1]) continue;

        ans = max(ans, a[l0] + a[i-1] + a[l1] + a[l1-1] + a[l1-2] + a[l1-3] + a[l1-4]);
    }

    cout << ans;
}