#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <map>
#include <set>
#include <climits>
#include <cmath>
#include <fstream>
#include <queue>
using namespace std;
const int MAXN = 2005;
int n, a, b;
vector<int> nums;
int dp[MAXN][MAXN];
int idx(int val) {
int ans = -1;
int lo = 0, hi = n - 1;
while (lo <= hi) {
int mid = (lo + hi) / 2;
if (nums[mid] < val) {
lo = mid + 1;
ans = max(ans, mid);
}
else {
hi = mid - 1;
}
}
return ans;
}
bool check(int mid) {
int calc1[MAXN], calc2[MAXN];
for (int i = 0; i < n; i++) {
calc1[i] = idx(nums[i] - mid + 1);
calc2[i] = idx(nums[i] - 2 * mid + 1);
}
for (int i = 0; i < n; i++) {
int cur = idx(nums[i] - 2 * mid + 1);
if (cur == -1) {
dp[i][0] = 1;
}
else {
dp[i][0] = dp[cur][0] + 1;
}
}
for (int i = 0; i < n; i++) {
for (int j = 1; j <= min(a, n); j++) {
int val1 = calc1[i];
int val2 = calc2[i];
int c1 = INT_MAX, c2 = INT_MAX;
if (val1 == -1) {
c1 = 0;
}
else {
c1 = dp[val1][j - 1];
}
if (val2 == -1) {
c2 = 1;
}
else {
c2 = dp[val2][j] + 1;
}
dp[i][j] = min(c1, c2);
}
}
for (int i = 0; i <= min(a, n); i++) {
if (dp[n - 1][i] <= b) {
return true;
}
}
return false;
}
int main() {
cin >> n >> a >> b;
for (int i = 0; i < n; i++) {
int temp;
cin >> temp;
nums.push_back(temp);
}
sort(nums.begin(), nums.end());
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
dp[i][j] = (int)1e9;
}
}
int lo = 1;
int hi = (int)1e9;
int ans = INT_MAX;
while (lo <= hi) {
int mid = (lo + hi) / 2;
if (check(mid)) {
ans = min(ans, mid);
hi = mid - 1;
}
else {
lo = mid + 1;
}
}
cout << ans << endl;
}
