#include<bits/stdc++.h>
using namespace std;
const int MAXN = 2000;
const int MAXA = 1e9;
const int INF = 1e9;
int N, P, Q;
int A[MAXN + 5];
int nextP[MAXN + 5], nextQ[MAXN + 5];
int DP[MAXN + 5][MAXN + 5];
int f(int idx, int p) {
if (p < 0) return INF;
if (idx == N) return 0;
int &ret = DP[idx][p];
if (ret != -1) return ret;
return ret = min(f(nextP[idx], p - 1), f(nextQ[idx], p) + 1);
}
bool valid(int w) {
for (int i = 0; i < N; i++) {
nextP[i] = nextQ[i] = N;
for (int j = i + 1; j < N; j++) {
if (A[j] - A[i] + 1 > w) {
nextP[i] = j;
break;
}
}
for (int j = i + 1; j < N; j++) {
if (A[j] - A[i] + 1 > 2 * w) {
nextQ[i] = j;
break;
}
}
}
memset(DP, -1, sizeof DP);
return f(0, P) <= Q;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> N >> P >> Q;
for (int i = 0; i < N; i++) cin >> A[i];
if (P + Q >= N) {
cout << 1 << endl;
return 0;
}
sort(A, A + N);
int l = 1, r = MAXA, ans = INF, mid;
while (l <= r) {
mid = (l + r) / 2;
if (valid(mid)) {
ans = min(ans, mid);
r = mid - 1;
}
else l = mid + 1;
}
cout << ans << endl;
}
