import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.util.ArrayDeque;
import java.io.InputStreamReader;
import java.io.InputStream;
/**
* Built using CHelper plug-in
* Actual solution is at the top
*/
public class watching {
public static void main(String[] args) {
InputStream inputStream = System.in;
OutputStream outputStream = System.out;
InputReader in = new InputReader(inputStream);
PrintWriter out = new PrintWriter(outputStream);
Watching solver = new Watching();
solver.solve(1, in, out);
out.close();
}
static class Watching {
public void solve(int testNumber, InputReader in, PrintWriter out) {
int N = in.nextInt();
int P = in.nextInt();
int Q = in.nextInt();
if (P >= N || Q >= N) {
out.println(1);
} else {
int low = 1;
int high = (int) (1e9);
int[] A = new int[N];
for (int i = 0; i < N; i++) {
A[i] = in.nextInt();
}
ArrayUtils.sort(A);
while (low < high) {
int mid = (low + high) / 2;
int[] moveBig = new int[N];
int[] moveSmall = new int[N];
ArrayDeque<Integer> big = new ArrayDeque<>();
ArrayDeque<Integer> small = new ArrayDeque<>();
moveBig[N - 1] = N - 1;
moveSmall[N - 1] = N - 1;
big.add(A[N - 1]);
small.add(A[N - 1]);
for (int i = N - 2; i >= 0; i--) {
big.addFirst(A[i]);
small.addFirst(A[i]);
while (2 * mid + A[i] <= big.getLast()) {
big.removeLast();
}
while (mid + A[i] <= small.getLast()) {
small.removeLast();
}
moveBig[i] = i + big.size() - 1;
moveSmall[i] = i + small.size() - 1;
}
int[][] dp = new int[P + 1][Q + 1];
dp[0][0] = -1;
boolean flag = false;
cont:
for (int i = 0; i <= P; i++) {
for (int j = 0; j <= Q; j++) {
if (dp[i][j] == N - 1) {
flag = true;
break cont;
}
if (j + 1 <= Q) {
dp[i][j + 1] = Math.max(moveBig[dp[i][j] + 1], dp[i][j + 1]);
}
if (i + 1 <= P) {
dp[i + 1][j] = Math.max(moveSmall[dp[i][j] + 1], dp[i + 1][j]);
}
}
}
if (flag) {
high = mid;
} else {
low = mid + 1;
}
}
out.println(high);
}
}
}
static class ArrayUtils {
public static void shuffle(int[] arr) {
for (int i = 0; i < arr.length; i++) {
int rand = (int) (Math.random() * (i + 1));
swap(arr, i, rand);
}
}
public static void swap(int[] arr, int i, int j) {
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
public static void sort(int[] arr) {
shuffle(arr);
Arrays.sort(arr);
//get rid of quicksort cases
}
}
static class InputReader {
public BufferedReader reader;
public StringTokenizer tokenizer;
public InputReader(InputStream stream) {
reader = new BufferedReader(new InputStreamReader(stream), 32768);
tokenizer = null;
}
public String next() {
while (tokenizer == null || !tokenizer.hasMoreTokens()) {
try {
tokenizer = new StringTokenizer(reader.readLine());
} catch (IOException e) {
throw new RuntimeException(e);
}
}
return tokenizer.nextToken();
}
public int nextInt() {
return Integer.parseInt(next());
}
}
}
