#pragma GCC target ("avx")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define _USE_MATH_DEFINES
#include<iostream>
#include<string>
#include<queue>
#include<cmath>
#include<map>
#include<set>
#include<list>
#include<iomanip>
#include<vector>
#include<random>
#include<functional>
#include<algorithm>
#include<stack>
#include<cstdio>
#include<cstring>
#include<bitset>
#include<unordered_map>
#include<climits>
#include<fstream>
#include<complex>
#include<time.h>
#include<cassert>
#include<functional>
#include<numeric>
#include<tuple>
using namespace std;
using ll = long long;
using ld = long double;
#define int long long
#define all(a) (a).begin(),(a).end()
#define fs first
#define sc second
#define xx first
#define yy second.first
#define zz second.second
#define H pair<int, int>
#define P pair<int, pair<int, int>>
#define Q(i,j,k) mkp(i,mkp(j,k))
#define rng(i,s,n) for(int i = (s) ; i < (n) ; i++)
#define rep(i,n) rng(i, 0, (n))
#define mkp make_pair
#define vec vector
#define vi vec<int>
#define pb emplace_back
#define siz(a) (int)(a).size()
#define crdcomp(b) sort(all((b)));(b).erase(unique(all((b))),(b).end())
#define getidx(b,i) (lower_bound(all(b),(i))-(b).begin())
#define ssp(i,n) (i==(int)(n)-1?"\n":" ")
#define ctoi(c) (int)(c-'0')
#define itoc(c) (char)(c+'0')
#define cyes printf("Yes\n")
#define cno printf("No\n")
#define cdf(n) int quetimes_=(n);rep(qq123_,quetimes_)
#define gcj printf("Case #%lld: ",qq123_+1)
#define readv(a,n) a.resize(n,0);rep(i,(n)) a[i]=read()
#define found(a,x) (a.find(x)!=a.end())
//#define endl "\n"
constexpr int mod = (ll)1e9 + 7;
constexpr int Mod = 998244353;
constexpr ld EPS = 1e-10;
constexpr ll inf = (ll)3 * 1e18;
constexpr int Inf = (ll)15 * 1e8;
constexpr int dx[] = { -1,1,0,0 }, dy[] = { 0,0,-1,1 };
template<class T>bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; }
ll read() { ll u, k = scanf("%lld", &u); return u; }
string reads() { string s; cin >> s; return s; }
H readh(bool g = 0) { H u; int k = scanf("%lld %lld", &u.fs, &u.sc); if (g) u.fs--, u.sc--; return u; }
bool ina(H t, int h, int w) { return 0 <= t.fs && t.fs < h && 0 <= t.sc && t.sc < w; }
bool ina(int t, int l, int r) { return l <= t && t < r; }
ll gcd(ll i, ll j) { return j ? gcd(j, i % j) : i; }
ll popcount(ll x) {
    int sum = 0; for (int i = 0; i < 60; i++)if ((1ll << i) & x) sum++;
    return sum;
}
class mint {
public:ll v;
      mint(ll v = 0) { s(v % mod + mod); }
      constexpr static int mod = (ll)Mod;
      constexpr static int fn_ = (ll)3e5 + 5;
      static mint fact[fn_], comp[fn_];
      mint pow(int x) const {
          mint b(v), c(1);
          while (x) {
              if (x & 1) c *= b;
              b *= b;
              x >>= 1;
          }
          return c;
      }
      inline mint& s(int vv) {
          v = vv < mod ? vv : vv - mod;
          return *this;
      }
      inline mint inv()const { return pow(mod - 2); }
      inline mint operator-()const { return mint() - *this; }
      inline mint& operator+=(const mint b) { return s(v + b.v); }
      inline mint& operator-=(const mint b) { return s(v + mod - b.v); }
      inline mint& operator*=(const mint b) { v = v * b.v % mod; return *this; }
      inline mint& operator/=(const mint b) { v = v * b.inv().v % mod; return *this; }
      inline mint operator+(const mint b) const { return mint(v) += b; }
      inline mint operator-(const mint b) const { return mint(v) -= b; }
      inline mint operator*(const mint b) const { return mint(v) *= b; }
      inline mint operator/(const mint b) const { return mint(v) /= b; }
      friend ostream& operator<<(ostream& os, const mint& m) {
          return os << m.v;
      }
      friend istream& operator>>(istream& is, mint& m) {
          int x; is >> x; m = mint(x);
          return is;
      }
      bool operator<(const mint& r)const { return v < r.v; }
      bool operator>(const mint& r)const { return v > r.v; }
      bool operator<=(const mint& r)const { return v <= r.v; }
      bool operator>=(const mint& r)const { return v >= r.v; }
      bool operator==(const mint& r)const { return v == r.v; }
      bool operator!=(const mint& r)const { return v != r.v; }
      explicit operator bool()const { return v; }
      explicit operator int()const { return v; }
      mint comb(mint k) {
          if (k > * this) return mint();
          if (!fact[0]) combinit();
          if (v >= fn_) {
              if (k > * this - k) k = *this - k;
              mint tmp(1);
              for (int i = v; i >= v - k.v + 1; i--) tmp *= mint(i);
              return tmp * comp[k.v];
          }
          return fact[v] * comp[k.v] * comp[v - k.v];
      }//nCk
      mint perm(mint k) {
          if (k > * this) return mint();
          if (!fact[0]) combinit();
          if (v >= fn_) {
              mint tmp(1);
              for (int i = v; i >= v - k.v + 1; i--) tmp *= mint(i);
              return tmp;
          }
          return fact[v] * comp[v - k.v];
      }//nPk
      static void combinit() {
          fact[0] = 1;
          for (int i = 1; i < fn_; i++) fact[i] = fact[i - 1] * mint(i);
          comp[fn_ - 1] = fact[fn_ - 1].inv();
          for (int i = fn_ - 2; i >= 0; i--) comp[i] = comp[i + 1] * mint(i + 1);
      }
}; mint mint::fact[fn_], mint::comp[fn_];
//--------------------------------------------------------------

class SlideMaximam {
    deque<H>dat;//最初の値がどうか？で見ていく
    function<bool(H, H)> ope;//最大値とかを表現する 前>後？
    function<bool(H, int)> valid;//この値は適切か？
public:
    //maximam-> "<", !isvalid(value, now)->remove
    void init(function<bool(H, H)>operate, function<bool(H, int)>isvalid) {
        ope = operate, valid = isvalid;
    }
    //now, value, flag
    void push(H t) {
        remove(t.sc);
        while (!dat.empty() && ope(dat.back(), t)) 
            dat.pop_back();
        dat.push_back(t);
    }
    H top(int now) {
        remove(now);
        return dat.front();
    }
    void remove(int now) {
        while (!dat.empty() && !valid(dat.front(), now)) dat.pop_front();
    }
    bool empty(int now) { remove(now); return dat.empty(); }
};


//---------------------------------------------------------------------

int n, k, m;
int a[4000];
int dp[4000][4000];
//dp[i][j]=i番目まで処理をして、j個分の集合を生成した
SlideMaximam mus[4000], pus[4000];
//dp[?][j]=j個の集合を生成した時の最大値は何ですか？
//i-M<=?<=i-1の?の最大値を求めよ
//大小で求める

int mi[4000], pl[4000];


signed main() {
    cin >> n >> k >> m;
    rep(i, n) cin >> a[i];
    mi[0] = -a[0]; pl[0] = a[0];
    rng(i, 1, n) mi[i] = mi[i - 1] - a[i], pl[i] = pl[i - 1] + a[i];

    rep(i, k + 1) {
        mus[i].init([&](H a, H b) ->bool {return a.fs < b.fs; }, [&](H a, int now) {return a.sc >= now - m; });
        pus[i].init([&](H a, H b) ->bool {return a.fs < b.fs; }, [&](H a, int now) {return a.sc >= now - m; });
    }
    rep(i, n) {
        for (int j = k; j > 1; j--) {
            //ヤバい最大値を消し飛ばしていけー
            if (mus[j - 1].empty(i)) continue;
            dp[i][j] = max(mus[j - 1].top(i).fs - mi[n - 1] + mi[i], pus[j - 1].top(i).fs - pl[n - 1] + pl[i]);
            mus[j].push(H{ dp[i][j] + mi[n - 1] - mi[i], i });
            pus[j].push(H{ dp[i][j] + pl[n - 1] - pl[i], i });
        }
        if (i < m) {
            dp[i][1] = max(mi[i], pl[i]);
            mus[1].push(H{ dp[i][1] + mi[n - 1] - mi[i], i });
            pus[1].push(H{ dp[i][1] + pl[n - 1] - pl[i], i });
        }
    }
    cout << dp[n - 1][k] << endl;
}