#include <iostream>
#include <vector>
 
using namespace std;
 
#define FOR(i,a,b) for(int i=a; i<=b; i++)
 
typedef long long LL;
 
int main()
{
	int n;
	cin>>n;
	vector<LL> a,f,g,h;
	a.resize(n+1);
	f.resize(n+1);
	g.resize(n+1);
	h.resize(n+1);
 
	FOR(i,1,n)
		cin>>a[i];
 
	f[1] = a[1];
	FOR(i,2,n)
		f[i] = max(f[i-1],a[i]);
 
	g[2] = 2*a[2] + a[1]; 
	FOR(i,3,n)
		g[i] = max(g[i-1],2*a[i] + f[i-1]);
 
	h[3] = 3*a[3] + 2*a[2] + a[1];
	FOR(i,4,n)
		h[i] = max(h[i-1],3*a[i] + g[i-1]);
 
	cout<<h[n]<<endl;
 
	return 0;
}

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NSAKLTEgMiAtMiAtMyA1

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