#include<bits/stdc++.h>
using namespace std;
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;

template<typename T1,typename T2>
ostream &operator<<(ostream &os,const pair<T1,T2>&p){
    os<<p.first<<" "<<p.second;
    return os;
}

template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==v.size()?"":" ");
    return os;
}

ll dp[3010][3010];
ll a[3010],sum[3010];

signed main(){
    rep(i,3010)rep(j,3010)dp[i][j]=-LINF;
    dp[0][0]=0;

    int n,k,m;cin>>n>>k>>m;
    rep(i,n){
        cin>>a[i];
        sum[i+1]=a[i]+sum[i];
    }

    rep(j,k){
        deque<ll>d1,d2;// dp-sum,dp+sum
        vector<ll>sm1,sm2;
        rep(i,n+1){
            while(!d1.empty() and dp[d1.back()][j]-sum[d1.back()]<=dp[i][j]-sum[i]) d1.pop_back();
            d1.push_back(i);
            sm1.push_back(dp[d1.front()][j]-sum[d1.front()]);
            if(d1.front()==i-m+1) d1.pop_front();
        }
        rep(i,n+1){
            while(!d2.empty() and dp[d2.back()][j]+sum[d2.back()]<=dp[i][j]+sum[i]) d2.pop_back();
            d2.push_back(i);
            sm2.push_back(dp[d2.front()][j]+sum[d2.front()]);
            if(d2.front()==i-m+1) d2.pop_front();
        }
        rep(i,n){
            chmax(dp[i+1][j+1],sm1[i]+sum[i+1]);
            chmax(dp[i+1][j+1],sm2[i]-sum[i+1]);
        }
    }
    cout<<dp[n][k]<<endl;
    return 0;
}