/*
ID:
LANG: C++
TASK:
*/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define ff first
#define ss second
const int NMAX = 2e3+2, INF = 1e8;
ll n, p, q;
vector <ll> arr;
ll dp[NMAX][NMAX];
bool seen[NMAX][NMAX];
ll Play(int i, ll pres, ll w) {
//cerr << "i=" << i << "; pres=" << pres << endl;
// caso base
if (i >= n) return 0LL;
// caso dp
if (seen[i][pres]) return dp[i][pres];
// caso recursivo
else {
ll res1 = INF, res2 = INF;
// tomo un p
int j=i;
while (j+1<n && arr[j+1]-arr[i]+1<=w) j++;
if (pres) res1 = Play(j+1, pres-1, w);
// tomo un q
while (j+1<n && arr[j+1]-arr[i]+1<=2*w) j++;
res2 = Play(j+1, pres, w) + 1LL;
seen[i][pres] = true;
return dp[i][pres] = min(res1, res2);
}
}
bool Check(ll w) {
//cerr << "---" << endl << "Checkeo con w=" << w << endl;
// ponemos la dp en forma
memset(seen, false, sizeof(seen));
for (int i=0; i<NMAX; i++) dp[0][i] = 0LL;
if (Play(0, p, w) <= q) return true;
else return false;
}
int main() {
/*//
freopen("watching.in", "r", stdin);
freopen("", "w", stdout);
//*/
cin >> n >> p >> q;
arr.resize(n);
for (int i=0; i<n; i++) cin >> arr[i];
sort(arr.begin(), arr.end());
/*//
cerr << "A: [";
for (int x : arr) cerr << x << ", ";
cerr << "]" << endl;
//*/
if (p+q>=n) {
cout << 1 << endl;
exit(0);
}
ll lb = 1, ub = 1e9, mid;
while (lb <= ub) {
mid = (lb+ub)/2;
if (Check(mid)) ub = mid-1;
else lb = mid+1;
}
cout << ub+1 << endl;
return 0;
}
