#include<bits/stdc++.h>

#define rep(i,x,y) for(register int i=x;i<=y;i++)

#define ll long long

using namespace std;

const int N=;

const int Logn=;

inline int read(){

    int x=,f=;char ch=getchar();

    while(!isdigit(ch)){if(ch=='-')f=-;ch=getchar();}

    while(isdigit(ch)){x=(x<<)+(x<<)+(ch^);ch=getchar();}

    return x*f;}

namespace zjc{

    int n,k,L,R,a[N],sum[N],f[N][Logn],lg[N];ll ans;

    struct node{int op,l,r,t;

        friend bool operator <(node x,node y){

        return sum[x.t]-sum[x.op-]<sum[y.t]-sum[y.op-];}

    };priority_queue<node> q;

    void init(){

        lg[]=-;

        rep(i,,n) f[i][]=i,lg[i]=lg[i>>]+;

        rep(j,,Logn)for(int i=;i+(<<j)-<=n;i++)

        f[i][j]=sum[f[i][j-]]>sum[f[i+(<<j-)][j-]]?f[i][j-]:f[i+(<<j-)][j-];

    }

    int query(int x,int y){

        int s=lg[y-x+];

        return sum[f[x][s]]>sum[f[y-(<<s)+][s]]?f[x][s]:f[y-(<<s)+][s];

    }

    void work(){

        n=read(),k=read(),L=read(),R=read();

        rep(i,,n) a[i]=read(),sum[i]=sum[i-]+a[i];

        init();

        for(int i=;i+L-<=n;i++){

            int l=i+L-,r=min(i+R-,n);

            int t=query(l,r);

            q.push((node){i,l,r,t});

        }

        for(int i=;i<=k;i++){

            node u=q.top();q.pop();

            ans+=sum[u.t]-sum[u.op-];

            if(u.l<=u.t-) q.push((node){u.op,u.l,u.t-,query(u.l,u.t-)});

            if(u.t+<=u.r) q.push((node){u.op,u.t+,u.r,query(u.t+,u.r)});

        }

        printf("%lld\n",ans);return;

    }

}

int main(){

    freopen("seq.in","r",stdin);

    freopen("seq.out","w",stdout);

    zjc::work();

    return ;

}