#include <bits/stdc++.h>
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int n, p, q;
std::cin >> n >> p >> q;
std::vector<int> a(n);
for (int i = 0; i < n; i++) {
std::cin >> a[i];
}
if (p + q >= n) {
std::cout << 1 << "\n";
return 0;
}
sort(a.begin(), a.end());
auto check = [&](int len) {
std::vector<std::vector<int>> dp(n + 1, std::vector<int>(q + 1, 1e9));
dp[0][0] = 0;
int p1 = 1, p2 = 1;
for (int i = 1; i <= n; i++) {
while (a[i - 1] - a[p1 - 1] >= len) p1++;
while (a[i - 1] - a[p2 - 1] >= 2 * len) p2++;
for (int Q = 0; Q <= q; Q++) {
dp[i][Q] = std::min(dp[i][Q], dp[p1 - 1][Q] + 1);
if (Q) {
dp[i][Q] = std::min(dp[i][Q], dp[i][Q - 1]);
dp[i][Q] = std::min(dp[i][Q], dp[p2 - 1][Q - 1]);
}
}
}
return dp[n][q] <= p;
};
// for (int i = 1; i <= 17; i++) std::cerr << check(i) << "\n";
// return 0;
int l = 0, r = 1000000007;
while (l + 1 < r) {
int mid = (l + r) / 2;
if (check(mid)) {
r = mid;
} else {
l = mid;
}
}
std::cout << r << "\n";
return 0;
}
