#include <bits/stdc++.h>
using namespace std;
template <class T> void chmax(T& a, const T b){a=max(a,b);}

template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}

void balance(multiset<long long>& stl,multiset<long long>& str) {
	while(stl.size()>str.size()+1) {
		long long tmp = *stl.rbegin();
		str.insert(tmp);
		stl.erase(stl.find(tmp));
	}
	while(stl.size()<str.size()) {
		stl.insert(*str.begin());
		str.erase(str.begin());
	}
}

int main() {
	int N; cin >> N;
	vector<long long> A(N);
	for(int i = 0; i < N; ++i) cin >> A[i];
	vector<vector<pair<int,int>>> asc(N+1),desc(N+1);
	vector<pair<int,int>> range;
	for(int i = 1; i <= N; ++i) {
		for(int j = 0; j+i <= N; j+=i) {
			asc[i].push_back({j,j+i-1});
			range.push_back({j,j+i-1});
		}
		for(int j = N; 0 <= j-i; j-=i) {
			desc[i].push_back({j-i,j-1});
			range.push_back({j-i,j-1});
		}
		reverse(desc[i].begin(),desc[i].end());
	}
	int Q = range.size();
	int bucket = sqrt(N);
	vector<int> idx(Q);
	iota(idx.begin(),idx.end(),0);
	sort(idx.begin(),idx.end(),[&](int a, int b){
		int& al = range[a].first;
		int& ar = range[a].second;
		int& bl = range[b].first;
		int& br = range[b].second;
		return (al/bucket != bl/bucket) ? (al/bucket < bl/bucket) : (ar < br);
	});
	int l = 0, r = 0;
	multiset<long long> stl,str;
	stl.insert(A[0]);
	map<pair<int,int>,long long> mp;
	for(int& i:idx){
		int& xl = range[i].first;
		int& xr = range[i].second;
		while(l < xl){
			if(stl.count(A[l])) stl.erase(stl.find(A[l]));
			else str.erase(str.find(A[l]));
			l++;
			balance(stl,str);
		}
		while(xl < l){
			l--;
			stl.insert(A[l]);
			if(str.size()){
				long long tmpl = *stl.rbegin();
				long long tmpr = *str.begin();
				if(tmpl>tmpr) {
					stl.erase(stl.find(tmpl));
					stl.insert(tmpr);
					str.erase(str.find(tmpr));
					str.insert(tmpl);
				}
			}
			balance(stl,str);
		}
		while(r < xr){
			r++;
			stl.insert(A[r]);
			if(str.size()){
				long long tmpl = *stl.rbegin();
				long long tmpr = *str.begin();
				if(tmpl>tmpr) {
					stl.erase(stl.find(tmpl));
					stl.insert(tmpr);
					str.erase(str.find(tmpr));
					str.insert(tmpl);
				}
			}
			balance(stl,str);
		}
		while(xr < r){
			if(stl.count(A[r])) stl.erase(stl.find(A[r]));
			else str.erase(str.find(A[r]));
			r--;
			balance(stl,str);
		}
		if(l==xl && r==xr) mp[{xl,xr}] = *stl.rbegin();
	}

	long long ans = 0;
	for(int i = 1; i <= N; ++i) {
		int M = N/i;
		vector<long long> sumasc(M,0),sumdesc(M,0);
		for(int j = 0; j < M; ++j)    sumasc[j]   = mp[asc[i][j]];
		for(int j = M-1; 0 <= j; --j) sumdesc[j]  = mp[desc[i][j]];
		for(int j = 1; j < M; ++j)    sumasc[j]  += sumasc[j-1];
		for(int j = M-2; 0 <= j; --j) sumdesc[j] += sumdesc[j+1];
		for(int j = 1; j < M; ++j)    chmax(sumasc[j],sumasc[j-1]);
		for(int j = M-2; 0 <= j; --j) chmax(sumdesc[j],sumdesc[j+1]);
		chmax(ans,sumasc[M-1]);
		chmax(ans,sumdesc[0]);

		int k = 0;
		for(int j = 0; j < M; ++j) {
			while(k < M && asc[i][j].second >= desc[i][k].first) k++;
			if(k<M && asc[i][j].second < desc[i][k].first) {
				chmax(ans,sumasc[j]+sumdesc[k]);
			}
		}

	}
	cout << ans << endl;
    return 0;
}