#include <bits/stdc++.h>
using namespace std;
const int N=105;
int n,p,q;
int a[N];
bool f(int w){
vector<int>dp[2];
dp[0]=dp[1]=vector<int>(q+2);
for(int i=0;i<=p;i++){
dp[0]=dp[1];
for(int j=0;j<=q;j++){
int pos=dp[0][j];
pos=min(pos,n-1);
dp[1][j]=upper_bound(a+1,a+n+1,a[pos+1]+w-1)-a-1;
int&x=dp[0][j+1];
x=max(x,(int)(upper_bound(a+1,a+n+1,a[pos+1]+2*w-1)-a-1));
}
}
//cout<<dp[0][q]<<endl;
return dp[0][q]>=n;
}
int main(){
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;
}
