#include <bits/stdc++.h>
using namespace std;
int N,P,Q;
int events[2001], prep[2001], preq[2001], minq[2001][2001];
bool f (int w){
for (int i=N-1; i>=0; i--){
prep[i] = int(lower_bound(events, events+N, events[i]+w)-events);
preq[i] = int(lower_bound(events, events+N, events[i]+min(1000000001, 2*w))-events);
for (int p=0; p<=P; p++){
/*if (q==0) minp[i][q] = minp[prep[i]-1][q]+1;
else minp[i][q] = min(minp[prep[i]-1][q]+1 , minp[preq[i]-1][q-1]);*/
minq[i][p] = 1000000001;
if (p>0) minq[i][p] = minq[prep[i]][p-1];
minq[i][p] = min( minq[i][p], minq[preq[i]][p]+1 );
}
}
if (minq[0][P]<=Q) return true;
else return false;
}
int binarySearch(){
int L=0; int R=1000000001;
while (L<R){
int middle = (L+R)/2;
if (f(middle)){
R = middle;
}
else{
L = middle+1;
}
}
return L;
}
int main(){
cin >> N >> P >> Q;
for (int i=0; i<N; i++){
cin >> events[i];
}
if ((P+Q)>=N){
cout << 1;
return 0;
}
sort(events,events+N);
cout << binarySearch();
}
