#include <bits/stdc++.h>
#include <iostream>
using namespace std;
//typedef int64_t llo;
#define mp make_pair
#define a first
#define b second
#define pb push_back
int it[1000001];
int dp[2001][2001];
int n,p,q;
bool check(int mid){
for(int i=0;i<p+1;i++){
for(int j=0;j<p+1;j++){
dp[i][j]=0;
}
}
for(int i=0;i<p+1;i++){
for(int j=0;j<q+1;j++){
if(i==0 and j==0){
continue;
}
if(i>0){
if(dp[i-1][j]==n){
dp[i][j]=n;
}
dp[i][j]=max(dp[i][j],(int)(lower_bound(it,it+n,it[dp[i-1][j]]+mid)-it));
}
if(j>0){
if(dp[i][j-1]==n){
dp[i][j]=n;
}
dp[i][j]=max(dp[i][j],(int)(lower_bound(it,it+n,it[dp[i][j-1]]+2*mid)-it));
}
}
}
return dp[p][q]>=(n);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin>>n>>p>>q;
for(int i=0;i<n;i++){
cin>>it[i];
}
sort(it,it+n);
p=min(p,n);
q=min(q,n);
int low=1;
int high=1000000000;
while(low<high-1){
int mid=(low+high)/2;
if(check(mid)){
high=mid;
}
else{
low=mid;
}
}
int ans=high;
if(check(low)){
ans=min(ans,low);
}
cout<<ans<<endl;
return 0;
}
