#include<cstdio>

#include<deque>

#include<algorithm>

using namespace std;

const int maxn = 400000+3;

const long long inf  = -1000000000;

int n,l,r, w[maxn];

long long d[maxn];

struct Node{

    int pos;

    long long val;

    Node(int pos=0,long long val=0):pos(pos),val(val){}

};

deque<Node>Q;

inline void update(int cur)

{

    while(!Q.empty() && Q.front().pos < cur )Q.pop_front();

}

inline void insert_x(Node a)

{

    while(!Q.empty() && Q.front().val <= a.val)Q.pop_back();

    Q.push_back(a);

}

int main(){

    //freopen("in.txt","r",stdin);

    long long  ans = inf;

    scanf("%d%d%d",&n,&l,&r);

    for(int i =0;i <= n;++i)scanf("%d",&w[i]);

    d[0] = w[0];

    for(int i = 1;i<=n+l;++i){

        int left = i-r, right = i-l;

        if(right < 0) d[i] = inf;

        else{

            update(left);

            insert_x(Node(right,d[right]));

            d[i] =(long long) w[i] + Q.front().val;

            if(i>n) ans = max(ans, d[i]);

        }

    }

    printf("%lld",ans);

    return 0;

}