#include<iostream>

#include<cstring>

#include<cstdlib>

#include<cstdio>

#include<queue>

#include<cmath>

#define ll long long

using namespace std;

const int maxn=;

struct poi{int sum, l, r, x;};

priority_queue<poi>q;

int n, k, l, r;

int sum[maxn], f[maxn][];

ll ans;

void read(int &k)

{

    int f=; k=; char c=getchar();

    while(c<'' || c>'') c=='-' && (f=-), c=getchar();

    while(c<='' && c>='') k=k*+c-'', c=getchar();

    k*=f;

}

inline int min(int a, int b){return sum[a]<sum[b]?a:b;}

inline int querymin(int l, int r)

{

    bool flag=; if(!l) l++, flag=;

    if(l>r) return ;

    int k=log2(r-l+), ans=min(f[l][k], f[r-(<<k)+][k]);

    return flag?min(, ans):ans;

}

bool operator<(poi a, poi b) {return a.sum<b.sum;}

int main()

{

    read(n); read(k); read(l); read(r);

    for(int i=;i<=n;i++) read(sum[i]), sum[i]+=sum[i-], f[i][]=i;

    for(int j=;j<=log2(n);j++)

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

    f[i][j]=min(f[i][j-], f[i+(<<(j-))][j-]);

    for(int i=l;i<=n;i++) q.push((poi){sum[f[i][]]-sum[querymin(max(, i-r), i-l)], max(, i-r), i-l, i});

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

    {

        poi t=q.top(); q.pop();

        ans+=t.sum; int x=querymin(t.l, t.r);

        if(x!=t.l) q.push((poi){sum[f[t.x][]]-sum[querymin(t.l, x-)], t.l, x-, t.x});

        if(x!=t.r) q.push((poi){sum[f[t.x][]]-sum[querymin(x+, t.r)], x+, t.r, t.x});

    }

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

    return ;

}