#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
using namespace std;
const int N=2005;
int n,p,q;
int a[N];
vector<vector<int>>dp(2,vector<int>(N));
bool f(int w){
for(int i=0;i<=p;i++){
if(i){
dp[0]=dp[1];
}else{
dp[0].assign(q+2,0);
}
for(int j=0;j<=q;j++){
int pos=dp[0][j];
pos=min(pos,n-1);
dp[1][j]=upper_bound(a+pos+1,a+n+1,a[pos+1]+w-1)-a-1;
int&x=dp[0][j+1];
x=max(x,(int)(upper_bound(a+pos+1,a+n+1,a[pos+1]+2*w-1)-a-1));
}
}
//cout<<dp[0][q]<<endl;
return dp[0][q]>=n;
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>p>>q;
for(int i=1;i<=n;i++){
cin>>a[i];
}
if(n<=p+q){
cout<<1;
return 0;
}
sort(a+1,a+n+1);
//cout<<f(4)<<endl;
int l=1,r=1e9;
while(l<r){
int mid=(l+r)/2;
if(f(mid)){
r=mid;
}else{
l=mid+1;
}
}
cout<<l;
}
