#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define popcount __builtin_popcount
#define all(a) (a).begin(), (a).end()
using namespace std;
using namespace chrono;
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T,null_type,less_equal<>,rb_tree_tag,tree_order_statistics_node_update>;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, p, q; cin >> n >> p >> q;
p = min(p, n);
q = min(q, n);
long long A[n+1];
for (int i = 0; i < n; cin >> A[i++]);
A[n] = 2e9;
sort(A, A + n);
auto check = [&](int w) {
vector<vector<int>> dp(n+1, vector<int>(p+1));
int ptr1 = n, ptr2 = n;
for (int i = n-1; i >= 0; i--) {
dp[i].assign(p+1, 1e9);
while (0 < ptr1 && A[i] + w <= A[ptr1 - 1]) ptr1--;
while (0 < ptr2 && A[i] + 2*w <= A[ptr2 - 1]) ptr2--;
for (int j = 0; j <= p; j++) {
dp[i][j] = dp[ptr2][j] + 1;
if (0 < j)
dp[i][j] = min(dp[i][j], dp[ptr1][j-1]);
}
}
return dp[0][p] <= q;
};
int l = 0, r = 1e9;
while (r-l > 1) {
int mid = (l+r)/2;
(check(mid) ? r : l) = mid;
}
cout << r;
}
