#include <iostream>
#include <algorithm>
#include <vector>
#include <random>
#include <chrono>
#include <set>
#include <map>
#include <stack>
#include <functional>
#include <iomanip>
#include <queue>
#include <cassert>
#include <complex>
#include <cstring>
#include <memory>
#include <bitset>
#include <sstream>
#include <cmath>
#include <numeric>
#include <numbers>
#include <fstream>
using namespace std;
#ifndef template
#ifndef define
#define ll long long
#define ld long double
#define pl pair<ll, ll>
#define pi pair<int, int>
#define nl cout << '\n';
#define x first
#define y second
#define cbit(x) __builtin_popcountll(x)
#define uid(a, b) uniform_int_distribution<ll>(a, b)(rng)
#define siz(x) (int)x.size()
#endif
#ifndef print
void print(size_t x) {cout << x << ' ';}
void print(int x) {cout << x << ' ';}
void print(long long x) {cout << x << ' ';}
void print(float x) {cout << x << ' ';}
void print(long double x) {cout << x << ' ';}
void print(char x) {cout << x << ' ';}
void print(const char* x) {cout << x << ' ';}
void print(bool x) {cout << x << ' ';}
void print(string &x) {cout << x << ' ';}
template<typename T, typename V>
void print(pair<T, V> &p) {print(p.x); print(p.y);}
template<typename T>
void print(vector<T> v) {for (int i = 0; i < v.size(); i++) print(v[i]);}
template<typename T>
void print(vector<vector<T>> v) {
for (int i = 0; i < v.size(); i++){
for (int j = 0; j < v[i].size(); j++)
print(v[i][j]);
nl;
}
}
template <typename T, typename... V>
void print(T t, V&&... v) {print(t); print(v...);}
#endif
#ifndef read
void read(int &x) {cin >> x;}
void read(long long &x) {cin >> x;}
void read(unsigned &x) {cin >> x;}
void read(unsigned long long &x) {cin >> x;}
void read(float &x) {cin >> x;}
void read(long double &x) {cin >> x;}
void read(char &x) {cin >> x;}
void read(string &x) {cin >> x;}
void read(bool &x) {cin >> x;}
template<typename T>
void read(vector<T> &v) {
for (int i = 0; i < v.size(); i++)
read(v[i]);
}
template <typename T, typename... V>
void read(T &t, V&... v) {read(t); read(v...);}
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class T> bool maxi(T& a, const T& b) {
return a < b ? a = b, 1 : 0;
}
template<class T> bool mini(T& a, const T& b) {
return a > b ? a = b, 1 : 0;
}
template<class... Args>
auto vec(size_t n, Args&&... args) {
if constexpr(sizeof...(args) == 1)
return vector(n, args...);
else
return vector(n, vec(args...));
}
#endif
using namespace std;
const ll inf = 1e9;
const ll def = 2001;
const ll mod = 1e9+9;
using namespace std;
int dp[def][def];
void solve(){
int n, p, q;
read(n, p, q);
auto a = vec(n, 0);
read(a);
sort(a.begin(), a.end());
int l = 1, r = 1e9, mid = (l + r) / 2;
while (l < r){
auto nxt1 = vec(n, 0);
auto nxt2 = vec(n, 0);
for (int i = 0; i < n; i++){
nxt1[i] = upper_bound(a.begin(), a.end(), a[i] + mid - 1) - a.begin();
nxt2[i] = upper_bound(a.begin(), a.end(), a[i] + 2 * mid - 1) - a.begin();
}
for (int i = 0; i <= n; i++) for (int j = 0; j <= n; j++)
dp[i][j] = inf;
dp[0][0] = 0;
for (int i = 0; i < n; i++) for (int j = 0; j <= n; j++){
if (dp[i][j] == inf)
continue;
if (j < n)
mini(dp[nxt1[i]][j + 1], dp[i][j]);
mini(dp[nxt2[i]][j], dp[i][j] + 1);
}
bool ok = 0;
for (int i = 0; i <= p; i++){
if (dp[n][i] <= q)
ok = 1;
}
if (ok)
r = mid;
else
l = mid + 1;
mid = (l + r) / 2;
}
print(r);
}
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (ifstream("input.txt").good()){
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
}
int t = 1;
while (t--){
solve();
nl;
}
return 0;
}
