#include<bits/stdc++.h>
using namespace std;
int n,l,r,s,t,k=-1e9,a[100005],ans;
int main()
{
	cin>>n>>l>>r; s=n;
	for(int i=0;i<=n;i++)
		cin>>a[i-1];
	while(s>0) { k=-1e9;
		for(int i=t+l;i<=t+r;i++)
			k=max(k,a[i]);
		for(int i=t+l;i<=t+r;i++)
			if(k==a[i]) 
				s-=(i+1),ans+=a[i];
	} cout<<ans/2;
	return 0;
}