#include <bits/stdc++.h>
using namespace std;
int n, p, q;
int D[2020][2020], arr[2020];
bool check(int w)
{
if (w <= 0) return false;
int i,j=1,k=1,l;
for (i=1;i<=n;i++){
while (arr[i] - arr[j] >= w) j++;
while (arr[i] - arr[k] >= w * 2) k++;
for (l=0;l<=q;l++) D[i][l] = D[j-1][l] + 1;
for (l=0;l<=q;l++){
if (D[i][l+1] > D[k-1][l])
D[i][l+1] = D[k-1][l];
}
}
for (l=0;l<=q;l++) if (D[n][l] <= p) return true;
return false;
}
int main(){
cin>>n>>p>>q;
for(int i = 1; i <=n; i++){
cin>>arr[i];
}
sort(arr + 1, arr + n + 1);
if(n <= p + q)
cout<<1<<endl;
else{
int l = 1, r = 1000000000, mid;
while (l < r){
mid = (l + r) / 2;
if (check(mid)) r = mid - 1;
else l = mid + 1;
}
while(check(mid)) mid--;
while(!check(mid)) mid++;
cout<<mid<<endl;
return 0;
}
}
