// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
template<class T> using V = vector<T>;
const int INF = 1e9+10;
int main() {
cin.tie(0)->sync_with_stdio(0);
int N, P, Q; cin >> N >> P >> Q;
P = min(P, N + 1), Q = min(Q, N + 1);
V<int> A(N); for(auto& x : A) cin >> x;
sort(begin(A), end(A));
auto check = [&](int w) {
V<V<int>> dp(N + 1, V<int>(P + 1, INF));
dp[0][0] = 0;
int RW = 0, R2W = 0;
for(int i = 0; i < N; i++) for(int p = 0; p <= P; p++) {
// cout << i << " <-> " << p << endl;
if (p + 1 <= P) {
int x = A[i] + w - 1;
while(RW < N && A[RW] <= x) RW++;
// cout << i << " " << RW << endl;
dp[RW][p+1] = min(dp[RW][p+1], dp[i][p] + 1);
}
{
int x = A[i] + 2 * w - 1;
while(R2W < N && A[R2W] <= x) R2W++;
// cout << i << " " << R2W << endl;
dp[R2W][p] = min(dp[R2W][p], dp[i][p] + 1);
}
// cout << endl;
}
bool ans = 0;
for(int p = 0; p <= P; p++) {
int q = dp[N][p] - p;
if (q <= Q) ans = 1;
}
return ans;
};
int lo = 1, hi = INF / (P + Q);
while(lo < hi) {
int mid = (lo + hi) / 2;
if (check(mid)) hi = mid;
else lo = mid + 1;
}
cout << lo << nl;
return 0;
}
