#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include "bits/stdc++.h" // define macro "/D__MAI"

using namespace std;
typedef unsigned int uint;
typedef long long int ll;
typedef unsigned long long int ull;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define debugaar(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define repeat(l) for(auto cnt=0;cnt<(l);++cnt)
#define upto(l,r) for(auto cnt=l;cnt<=r;++cnt)
#define downto(r,l) for(auti cnt=r;cnt>=l;--cnt)
#define BIGINT 0x7FFFFFFF
#define MD 1000000007ll
#define PI 3.1415926535897932384626433832795
template<typename T1, typename T2>
ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << "(" << p.first << ":" << p.second << ")"; return o; }

#define TIME chrono::system_clock::now()
#define MILLISEC(t) (chrono::duration_cast<chrono::milliseconds>(t).count())
namespace {
    std::chrono::system_clock::time_point ttt;
    void tic() { ttt = TIME; }
    void toc() { fprintf(stderr, "TIME : %lldms\n", MILLISEC(TIME - ttt)); }
    std::chrono::system_clock::time_point tle = TIME;
#ifdef __MAI
    void safe_tle(int msec) { assert(MILLISEC(TIME - tle) < msec); }
#else
#define safe_tle(k) ;
#endif
}

#ifdef __MAI //_getchar_nolock
#define getchar_unlocked getchar
#endif
namespace {
    class MaiScanner {
    public:
        template<typename T>
        void input_integer(T& var) {
            var = 0;
            T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc&&cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var*sign;
        }
        inline int c() { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) {
            input_integer<int>(var);
            return *this;
        }
        inline MaiScanner& operator>>(long long& var) {
            input_integer<long long>(var);
            return *this;
        }
    };
}
MaiScanner scanner;


/*
def scan;gets.split.map(&:to_i);end


@n,@m = scan
@ww = scan

@memo = {}
def dfs(idx, lastflg, selected, firstflg)
return firstflg&&lastflg ? @ww[0] : 0 if idx == @n
key = [idx, lastflg, selected, firstflg]
return @memo[key] if @memo[key]
r = []
r <<  if selected < @m
r <<  if idx - selected < @n - @m
return @memo[key] = r.max
end

if @n == @m
p @ww.inject(:+)
elsif @m <= 1
p 0
else
p [dfs(1,false,0,false),dfs(1,true,1,true)].max
end

*/

int n, m;
int ww[3030];

int dp[3030][3030][2];
bool dpf[3030][3030][2];

void cleardp() {
    fill(&dp[0][0][0], &dp[3029][3029][1] + 1, 0);
    fill(&dpf[0][0][0], &dpf[3029][3029][1] + 1, 0);
}
bool sw_first = false;

ll dfs(int idx, int selected, int lastflg) {
    if (idx == n) return sw_first&&lastflg ? ww[0] : 0;

    if (dpf[idx][selected][lastflg]) return dp[idx][selected][lastflg];
    dpf[idx][selected][lastflg] = true;

    if (selected < m && idx - selected < n - m) {
        return dp[idx][selected][lastflg] = max(
            ((lastflg ? ww[idx] : 0) + dfs(idx + 1, selected + 1, true)),
            (dfs(idx + 1, selected, false))
        );
    }
    else if (!(selected < m)) {
        return dp[idx][selected][lastflg] = 
            (dfs(idx + 1, selected, false));
    }
    else {
        return dp[idx][selected][lastflg] =
            ((lastflg ? ww[idx] : 0) + dfs(idx + 1, selected + 1, true));
    }
}


int main() {
    scanner >> n >> m;

    repeat(n) {
        scanner >> ww[cnt];
    }

    if (n == m) {
        cout << accumulate(ww, ww + n, 0) << endl;
    }
    else if(m <= 1) {
        cout << 0 << endl;
    }
    else {
        ll result = dfs(1, 0, false);

        cleardp();
        sw_first = true;
        result = max(result, dfs(1, 1, true));

        cout << result << endl;
    }

    return 0;
}