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

typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
typedef vector<ll> vl;
typedef vector<vector<ll>> vvl;
//typedef vector<vector<ll>> Graph;

const ll mod = 1e9 + 7;
//const ll mod = 998244353;

#define REP(i,n) for(ll i=0;i<(ll)n;i++)
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define spa << " " <<
#define fi first
#define se second

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 (a>b) { a=b; return 1; } return 0; }

template<class S, class T> ostream& operator << (ostream& os, const pair<S, T> v){
os << "(" << v.first << ", " << v.second << ")"; return os;
}
template<class T> ostream& operator << (ostream& os, const vector<T> v){
for(int i = 0; i < (int)v.size(); i++){if(i > 0){os << " ";} os << v[i];} return os;
}
template<class T> ostream& operator << (ostream& os, const vector<vector<T>> v){
for(int i = 0; i < (int)v.size(); i++){if(i > 0){os << endl;} os << v[i];} return os;
}

template<typename T> void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++)
{cerr<<v[i][0];for(ll j=1;j<w;j++)cerr spa v[i][j];cerr<<endl;}};
template<typename T> void debug(vector<T>&v,ll n){if(n!=0)cerr<<v[0];
for(ll i=1;i<n;i++)cerr spa v[i];
cerr<<endl;};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    ll N, K, M;
    cin >> N >> K >> M;
    vl A(N);
    REP(i, N) cin >> A[i];

    const ll INF = (1ll<<60);
    vvl dp(N+1, vl(K+1, -INF));
    vvl tmp1(N+1, vl(K+1, -INF));
    vvl tmp2(N+1, vl(K+1, -INF));
    vl S(N+1, 0);
    REP(i, N) S[i+1] = S[i] + A[i]; 

    dp[0][0] = 0;
    
    for(int j=1;j<=K;j++){
        deque<ll> dq1, dq2;
        REP(i, N+1) tmp1[i][j-1] = dp[i][j-1] + S[i];
        REP(i, N+1) tmp2[i][j-1] = dp[i][j-1] - S[i];
        for(int i=1;i<=N;i++){
            while(!dq1.empty() and tmp1[dq1.back()][j-1] <= tmp1[i-1][j-1]){
                dq1.pop_back();
            }
            dq1.push_back(i-1);
            ll ma1 = tmp1[dq1.front()][j-1];
            if(dq1.front() == i-M) dq1.pop_front();

            while(!dq2.empty() and tmp2[dq2.back()][j-1] <= tmp2[i-1][j-1]){
                dq2.pop_back();
            }
            dq2.push_back(i-1);
            ll ma2 = tmp2[dq2.front()][j-1];
            if(dq2.front() == i-M) dq2.pop_front();

            chmax(dp[i][j], ma1 - S[i]);
            chmax(dp[i][j], ma2 + S[i]);
        }
    }

    cout << dp[N][K] << endl;

    return 0;
}