#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=2e5+3;
int n,m,L,R,trash,a[N];
int f[N],l=1,r,q[N],t[N],ans;
void insert(int i){
  while(l<=r&&q[r]<=f[i])r--;
  q[++r]=f[i],t[r]=i;
  while(l<=r&&i-t[l]>=m)l++;
}
signed main(){
  ios::sync_with_stdio(0);cin.tie(0),cout.tie(0);
  cin>>n>>L>>R>>trash;m=R-l+1;
  for(int i=1;i<=n;i++)cin>>a[i];
  for(int i=L;i<=n;i++){
    insert(i-L);
    f[i]=q[l]+a[i];
    if(i+R>n)ans=max(ans,f[i]);
  }
  cout<<ans<<'\n';
  return 0;
}