#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <cstring>
#include <functional>
#include <algorithm>
#include <bitset>
#include <numeric>

#define sk(i, x) for(uint64_t i = 0; i < x; i++) 
#define skc(i, start, x) for(uint64_t i = start; i < x; i++) 
#define skci(i, start, increment, x) for(uint64_t i = start; i < x; i+=increment) 


#define chin(x) char x; std::cin >> x;
#define slin(x) int64_t x; std::cin >> x
#define lin(x) uint64_t x; std::cin >> x
#define qsort(x) std::sort(x.begin(), x.end())
#define qmaxv(x) *std::max_element(x.begin(), x.end());
#define vsum(x) std::accumulate( x.begin(), x.end(), 0 )

typedef std::vector<int64_t> slv;
typedef std::vector<uint64_t> uslv;
typedef std::vector<int32_t> siv;
typedef std::vector<uint32_t> uiv;
typedef std::vector<bool> bv;




int main()
{
    lin( n );
    slv squares( n );
    sk( i, n )
    {
        slin( a );
        squares[i] = a;
    }
    int64_t highest_score = -999999;
    skc( start_pos, 1, n )
    {
        int64_t score = squares[0] + squares[n - 1];
        skci( i, start_pos, start_pos, n - 1 )
        {
            score += squares[i];
        }
        if( score > highest_score ) {
            highest_score = score;
        }
    }
    std::cout << highest_score << "\n";
    return 0;

}