#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
const int MAX = 2004;
int A[MAX], dp[MAX][MAX], pv[2][MAX];
int main() {
ios::sync_with_stdio(0); cin.tie(0);
int N, P, Q;
cin >> N >> P >> Q;
P = min(P, N); Q = min(Q, N);
for (int i = 1; i <= N; ++i) cin >> A[i];
sort(A + 1, A + N + 1);
ll l = 0, r = (ll)1e9 + 1;
while (l + 1 < r) {
ll mid = (l + r) >> 1;
for (int i = 1; i <= N; ++i) {
pv[0][i] = (upper_bound(A + 1, A + N + 1, A[i] - mid) - A) - 1;
pv[1][i] = (upper_bound(A + 1, A + N + 1, A[i] - 2LL * mid) - A) - 1;
}
memset(dp, 0x3f, sizeof(dp));
for (int q = 0; q <= Q; ++q) {
dp[q][0] = 0;
for (int i = 1; i <= N; ++i) {
if (q) dp[q][i] = dp[q - 1][pv[1][i]];
dp[q][i] = min(dp[q][i], dp[q][pv[0][i]] + 1);
}
}
(dp[Q][N] <= P ? r : l) = mid;
}
cout << r;
return 0;
}
