#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <cstring>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;

class RowGame { public:
	long long score(vector <int> board, int k) 
	{
		int N = board.size();
		vector<LL> best(N, -1);
		best[0] = 0;

		LL bestOfBest = 0;
		LL dif = -1, loopCnt = 0;

		int dir=+1;
		for(int ki=0; ki<k; ++ki, dir=-dir)
		{
			vector<LL> best2(N, -1);
			for(int s=0; s<N; ++s)
				if( best[s] >= 0 )
				{
					LL sum = 0;
					for(int t=s; 0<=t && t<N; t+=dir) {
						sum += board[t];
						if( best[s]+sum >= 0 )
						best2[t] = max(best2[t], best[s]+sum);
					}
				}
			best.swap(best2);
			LL bb2 = max(bestOfBest, *max_element(best.begin(), best.end()));
			{
				if( bb2-bestOfBest == dif )
					++loopCnt;
				else {
					loopCnt = 0;
					dif = bb2-bestOfBest;
				}
				if( loopCnt >= 2501 )
					return bestOfBest + dif*(k-ki);
			}
			bestOfBest = bb2;
		}
		return bestOfBest;
	}
};

// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
 { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
 { os << "{ ";
   for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
   os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const long long& Expected, const long long& Received) {
 bool ok = (Expected == Received);
 if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
 cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END	 verify_case(_, RowGame().score(board, k));}
int main(){

CASE(0)
	int board_[] = {2,-2,4,3,-10} ;
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = 3; 
	long long _ = 21LL; 
END
CASE(1)
	int board_[] = {-6,5};
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = 10; 
	long long _ = 0LL; 
END
CASE(2)
	int board_[] = {5,-6};
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = 10; 
	long long _ = 50LL; 
END
CASE(3)
	int board_[] = {10,-100,80};
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = 3; 
	long long _ = 30LL; 
END
CASE(4)
	int board_[] = {10,-100,80};
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = 4; 
	long long _ = 90LL; 
END
CASE(5)
	int board_[] = {-100,1,2,3,4,5,6,7,8,9,10,11,12,13,14};
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = 400000000; 
	long long _ = 41999999900LL; 
END
/*
CASE(6)
	int board_[] = ;
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = ; 
	long long _ = LL; 
END
CASE(7)
	int board_[] = ;
	  vector <int> board(board_, board_+sizeof(board_)/sizeof(*board_)); 
	int k = ; 
	long long _ = LL; 
END
*/
}
// END CUT HERE
