#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int N, P, Q;
int A[2005];
int dp[2005][2005]; // dp[tadbir_indeksi][ishlatilgan_kichik_kameralar] = minimal_katta_kameralar
int nextW[2005], next2W[2005];
// Berilgan w bilan barcha tadbirlarni yopish mumkinligini tekshirish
bool check(int w) {
if (P >= N || Q >= N) return true; // Agar kameralar tadbirlardan ko'p bo'lsa
// Oldindan har bir tadbir uchun kameralar qayergacha yetishini hisoblab chiqamiz
for (int i = 0; i < N; i++) {
nextW[i] = lower_bound(A, A + N, A[i] + w) - A;
next2W[i] = lower_bound(A, A + N, A[i] + 2 * w) - A;
}
// DP jadvalini cheksizlik bilan to'ldiramiz
for (int i = 0; i <= N; i++) {
for (int j = 0; j <= P; j++) dp[i][j] = Q + 1;
}
dp[0][0] = 0;
for (int i = 0; i < N; i++) {
for (int j = 0; j <= P; j++) {
if (dp[i][j] > Q) continue;
// 1. Kichik kamera ishlatish
if (j + 1 <= P) {
dp[nextW[i]][j + 1] = min(dp[nextW[i]][j + 1], dp[i][j]);
}
// 2. Katta kamera ishlatish
dp[next2W[i]][j] = min(dp[next2W[i]][j], dp[i][j] + 1);
}
}
// Oxirgi tadbirdan keyin birorta holatda katta kameralar soni Q dan oshmasa - true
for (int j = 0; j <= P; j++) {
if (dp[N][j] <= Q) return true;
}
return false;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> N >> P >> Q;
for (int i = 0; i < N; i++) cin >> A[i];
sort(A, A + N);
// Ikkilik qidiruv (Binary Search)
int low = 1, high = 1000000000, ans = 1000000000;
while (low <= high) {
int mid = low + (high - low) / 2;
if (check(mid)) {
ans = mid;
high = mid - 1;
} else {
low = mid + 1;
}
}
cout << ans << endl;
return 0;
}
