#include <bits/stdc++.h>
using namespace std;
#define LOCAL
#pragma region Macros
typedef long long ll;
#define ALL(x) (x).begin(),(x).end()
const long long MOD=1e9+7;
// const long long MOD=998244353;
const int INF=1e9;
const long long IINF=1e18;
const int dx[4]={1,0,-1,0},dy[4]={0,1,0,-1};
const char dir[4]={'D','R','U','L'};

template<typename T>
istream &operator>>(istream &is,vector<T> &v){
    for (T &x:v) is >> x;
    return is;
}
template<typename T>
ostream &operator<<(ostream &os,const vector<T> &v){
    for (int i=0;i<v.size();++i){
        os << v[i] << (i+1==v.size()?"": " ");
    }
    return os;
}
template<typename T,typename U>
ostream &operator<<(ostream &os,const pair<T,U> &p){
    cout << '(' << p.first << ',' << p.second << ')';
    return os;
}
template<typename T,typename U>
ostream &operator<<(ostream &os,const map<T,U> &m){
    os << '{';
    for (auto itr=m.begin();itr!=m.end();++itr){
        os << '(' << itr->first << ',' << itr->second << ')';
        if (++itr!=m.end()) os << ',';
        --itr;
    }
    os << '}';
    return os;
}
template<typename T>
ostream &operator<<(ostream &os,const set<T> &s){
    os << '{';
    for (auto itr=s.begin();itr!=s.end();++itr){
        os << *itr;
        if (++itr!=s.end()) os << ',';
        --itr;
    }
    os << '}';
    return os;
}

void debug_out(){cerr << '\n';}
template<class Head,class... Tail>
void debug_out(Head&& head,Tail&&... tail){
    cerr << head;
    if (sizeof...(Tail)>0) cerr << ", ";
    debug_out(move(tail)...);
}
#ifdef LOCAL
#define debug(...) cerr << " ";\
cerr << #__VA_ARGS__ << " :[" << __LINE__ << ":" << __FUNCTION__ << "]" << '\n';\
cerr << " ";\
debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

template<typename T> T gcd(T x,T y){return y!=0?gcd(y,x%y):x;}
template<typename T> T lcm(T x,T y){return x/gcd(x,y)*y;}

template<class T1,class T2> inline bool chmin(T1 &a,T2 b){
    if (a>b){a=b; return true;} return false;
}
template<class T1,class T2> inline bool chmax(T1 &a,T2 b){
    if (a<b){a=b; return true;} return false;
}
#pragma endregion

template<typename Monoid>
struct SegmentTree{
    typedef function<Monoid(Monoid,Monoid)> F;
    int n;
    F f;
    Monoid id;
    vector<Monoid> dat;
    SegmentTree(int n_,F f,Monoid id):f(f),id(id){init(n_);}
    void init(int n_){
        n=1;
        while(n<n_) n<<=1;
        dat.assign(n<<1,id);
    }
    void build(const vector<Monoid> &v){
        for (int i=0;i<v.size();++i) dat[i+n]=v[i];
        for (int i=n-1;i;--i) dat[i]=f(dat[i<<1|0],dat[i<<1|1]);
    }
    void update(int k,Monoid x){
        dat[k+=n]=x;
        while(k>>=1) dat[k]=f(dat[k<<1|0],dat[k<<1|1]);
    }
    Monoid query(int a,int b){
        if (a>=b) return id;
        Monoid vl=id,vr=id;
        for (int l=a+n,r=b+n;l<r;l>>=1,r>>=1){
            if (l&1) vl=f(vl,dat[l++]);
            if (r&1) vr=f(dat[--r],vr);
        }
        return f(vl,vr);
    }
    // most left position that meets condition "check"
    template<typename C>
    int find(int a,int b,const C &check,int k,int l,int r){
        if (!check(dat[k])||r<=a||b<=l) return -1;
        if (l+1==r) return k-n;
        int vl=find(a,b,check,k<<1|0,l,(l+r)>>1);
        if (~vl) return vl;
        return find(a,b,check,k<<1|1,(l+r)>>1,r);
    }
    template<typename C>
    int find(int a,int b,const C &check){
        return find(a,b,check,1,0,n);
    }
    Monoid operator[](int i){return dat[i+n];}
};

template<typename T>
vector<T> slide_min(const vector<T> &v,int k){
    deque<int> deq;
    vector<T> res;
    for (int i=0;i<v.size();++i){
        while(!deq.empty()&&v[deq.back()]>=v[i]) deq.pop_back();
        deq.push_back(i);
        if (i-k+1>=0){
            res.push_back(v[deq.front()]);
            if (deq.front()==i-k+1) deq.pop_front();
        }
    }
    return res;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N,K,M; cin >> N >> K >> M;
    vector<ll> A(N); cin >> A;
    vector<ll> sum(N+1,0);
    for (int i=0;i<N;++i) sum[i+1]=sum[i]+A[i];
    vector<vector<ll>> dp(N+1,vector<ll>(K+1,-IINF))
                        ,B(N+1,vector<ll>(K+1,-IINF))
                        ,C(N+1,vector<ll>(K+1,-IINF));
    dp[0][0]=B[0][0]=C[0][0]=0;
    vector<deque<ll>> deq1(K+1),deq2(K+1);
    deq1[0].emplace_back(0);
    deq2[0].emplace_back(0);
    for (int i=1;i<=N;++i){
        for (int j=K-1;j>=0;--j){
            if (!deq1[j].empty()) chmax(dp[i][j+1],B[deq1[j].front()][j]+sum[i]);
            if (!deq2[j].empty()) chmax(dp[i][j+1],C[deq2[j].front()][j]-sum[i]);
            B[i][j+1]=dp[i][j+1]-sum[i];
            while(!deq1[j+1].empty()&&B[deq1[j+1].back()][j+1]<=B[i][j+1]) deq1[j+1].pop_back();
            deq1[j+1].emplace_back(i);
            if (!deq1[j+1].empty()&&deq1[j+1].front()==i-M) deq1[j+1].pop_front();
            C[i][j+1]=dp[i][j+1]+sum[i];
            while(!deq2[j+1].empty()&&C[deq2[j+1].back()][j+1]<=C[i][j+1]) deq2[j+1].pop_back();
            deq2[j+1].emplace_back(i);
            if (!deq2[j+1].empty()&&deq2[j+1].front()==i-M) deq2[j+1].pop_front();
        }
        if (!deq1[0].empty()&&deq1[0].front()==i-M) deq1[0].pop_front();
        if (!deq2[0].empty()&&deq2[0].front()==i-M) deq2[0].pop_front();
    }
    cout << dp[N][K] << '\n';
}