#include <bits/stdc++.h>
using namespace std;

#define REP(i,m,n) for(int i=(m); i<(int)(n); i++)
#define RREP(i,m,n) for(int i=(int)((n)-1); i>=m; i--)
#define rep(i,n) REP(i,0,n)
#define rrep(i,n) RREP(i,0,n)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define fi first
#define se second
#define debug(...) {cerr<<"[L"<<__LINE__<<"] "; _debug(__VA_ARGS__);}

template<typename T>
string join(const vector<T>&v, string del=", "){ stringstream s;
    for(auto x : v) s << del << x; return s.str().substr(del.size());
}
template<typename T>
ostream& operator<<(ostream& o, const vector<T>&v){
    if(v.size()) o << "[" << join(v) << "]"; return o;
}
template<typename T>
ostream& operator<<(ostream& o, const vector<vector<T> >&vv){
    int l = vv.size();
    if(l){ o<<endl; rep(i,l) o << (i==0 ? "[ " : ",\n  " ) << vv[i] << (i==l-1 ? " ]" : ""); }
    return o;
}
template<typename T1, typename T2>
ostream& operator<<(ostream& o, const pair<T1, T2>& p){
    return o << "(" << p.first << ", " << p.second << ")";
}
inline void _debug(){cerr<<endl;}
template<class First, class... Rest>
void _debug(const First& first, const Rest&... rest){cerr<<first<<" ";_debug(rest...);}

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;

const double PI = (1*acos(0.0));
const double EPS = 1e-9;
const int INF = 0x3f3f3f3f;
const ll INFL = 0x3f3f3f3f3f3f3f3fLL;
const ll mod = 1e9 + 7;

inline void finput(string filename) {
    freopen(filename.c_str(), "r", stdin);
}

template <typename T>
struct SegTree{
    int n;
    vector<T> dat;
    SegTree(int sz, T val){
        n = 1;
        while(n < sz) n<<=1;
        dat.resize(2*n-1, val);
    }
    SegTree(vector<T> v): SegTree(v.size(), 0){
        for(int i=0; i<v.size(); i++) dat[i+n-1] = v[i];
        for(int i=n-2; i>=0; i--) dat[i] = max(dat[2*i+1], dat[2*i+2]);
    }
    void update(int i, T val){
        i += n - 1;
        dat[i] = val;
        while(i > 0){
            i = (i-1) / 2;
            dat[i] = max(dat[i*2+1], dat[i*2+2]);
        }
    }
    T query(int a, int b, int k=0, int l=0, int r=-1){
        if(r == -1) r = n;
        if(r<=a || b<=l) return -INFL;
        if(a<=l && r<=b) return dat[k];
        else{
            int v1 = query(a, b, k*2+1, l, (l+r)/2);
            int v2 = query(a, b, k*2+2, (l+r)/2, r);
            return max(v1, v2);
        }
    }
};

int main(){
    ios_base::sync_with_stdio(0);
    // finput("./input");
    int n,k,m; cin >> n >> k >> m;
    vl a(n);
    rep(i,n) cin >> a[i];

    auto st = SegTree<ll>(n+1, 0);
    vvl dp(k+1, vl(n+1, -INFL));
    dp[0][0] = 0;
    ll s;
    rep(i,k){
        s = 0;
        rep(j,n+1){
            if(j) dp[i+1][j] = max(dp[i+1][j], st.query(max(0,j-m), j) + s);
            if(j<n){
                st.update(j, dp[i][j] - s);
                s += a[j];
            }
        }
        s = 0;
        rep(j,n+1){
            if(j) dp[i+1][j] = max(dp[i+1][j], st.query(max(0,j-m), j) + s);
            if(j<n){
                st.update(j, dp[i][j] - s);
                s -= a[j];
            }
        }
    }
    cout << dp[k][n] << endl;
    return 0;
}