#include <bits/stdc++.h>
#define DIM 2010
#define INF 1000000000
using namespace std;
struct idk{
int poz,p,q;
};
deque <idk> c;
int v[DIM];
map <pair<int,pair<int,int> >, int> viz;
int n,p,q,i;
int get_poz (int x){
int st = 1, dr = n, sol = 0;
while (st <= dr){
int mid = (st+dr)>>1;
if (v[mid] <= x){
sol = mid;
st = mid+1;
} else dr = mid-1;
}
return sol;
}
int verif (int val){
int poz1 = get_poz (v[1] + val - 1);
int poz2 = get_poz (v[1] + 2 * val - 1);
c.clear(),viz.clear();
c.push_back({poz1,p-1,q});
c.push_back({poz2,p,q-1});
viz[make_pair(poz1,make_pair(p-1,q))] = 1;
viz[make_pair(poz2,make_pair(p,q-1))] = 1;
//viz[poz1][p-1][q] = 1;
//viz[poz2][p][q-1] = 1;
while (!c.empty()){
int poz = c.front().poz;
int p = c.front().p;
int q = c.front().q;
c.pop_front();
if (poz == n)
return 1;
if (p){
int new_poz = get_poz (v[poz+1] + val - 1);
if (!viz[make_pair(new_poz,make_pair(p-1,q))]){
viz[make_pair(new_poz,make_pair(p-1,q))] = 1;
c.push_back({new_poz,p-1,q});
}
}
if (q){
int new_poz = get_poz (v[poz+1] + 2 * val - 1);
if (!viz[make_pair(new_poz,make_pair(p,q-1))]){
viz[make_pair(new_poz,make_pair(p,q-1))] = 1;
c.push_back({new_poz,p,q-1});
}
}
}
return 0;
}
int main (){
//ifstream cin ("date.in");
//ofstream cout ("date.out");
cin>>n>>p>>q;
for (i=1;i<=n;i++)
cin>>v[i];
sort (v+1,v+n+1);
p = min (p,n), q = min (q,n);
int st = 0, dr = INF, sol = 0;
while (st <= dr){
int mid = (st+dr)>>1;
if (verif(mid)){
sol = mid;
dr = mid-1;
} else st = mid+1;
}
cout<<sol;
return 0;
}
