#include <bits/stdc++.h>
using namespace std;
#define int long long
#define form2(i, a, b) for (int i = (a); i < (b); ++i)
#define ford2(i, a, b) for (int i = (a-1); i >= (b); --i)
#define form(i, n) form2(i, 0, n)
#define ford(i, n) ford2(i, n, 0)
#define chmax(x, v) x = max(x, (v))
#define chmin(x, v) x = min(x, (v))
#define fi first
#define se second
const long long BIG = 1000000000000000000LL;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
void solve();
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0);
solve();
return 0;
}
const int borne = 2005;
vector<int> pos;
int gt[borne][2];
int dp[borne][borne];
int nbEv, nbPetits, nbGrands;
void comp(int small, int big, int longueur)
{
int &rep = dp[small][big];
rep = 0;
if (small) {
int cr = dp[small-1][big];
if (cr >= nbEv) { rep = cr; return; }
chmax(rep, gt[cr][0]);
}
if (big) {
int cr = dp[small][big-1];
if (cr >= nbEv) { rep = cr; return; }
chmax(rep, gt[cr][1]);
}
}
void cp(int longueur, int vers)
{
int i = 0, j = 0;
while (i < nbEv) {
while (j < nbEv && pos[j] < pos[i]+longueur) ++j;
gt[i][vers] = j;
++i;
}
}
bool ok(int longueur)
{
cp(longueur, 0); cp(2*longueur, 1);
form(smallUsed, nbPetits+1) form(bigUsed, nbGrands+1) {
if (smallUsed + bigUsed >= 1) {
comp(smallUsed, bigUsed, longueur);
}
}
return (dp[nbPetits][nbGrands] >= nbEv);
}
void solve()
{
cin >> nbEv >> nbPetits >> nbGrands;
pos.resize(nbEv);
form(i, nbEv) cin >> pos[i];
sort(pos.begin(), pos.end());
if (nbPetits + nbGrands >= nbEv) {
cout << "1\n";
return;
}
int l = 1, r = (int)(1e9) + 5;
while (l < r) {
int m = (l+r) / 2;
if (ok(m)) r = m;
else l = m+1;
}
cout << l << "\n";
}
