#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
#define pb push_back
#define f first
#define s second
const int MAXN = 2e3 + 10;
// dp[i][j] stores maximum number of small cameras left given j large left and all up to i inclusive is taken
int dp[MAXN][MAXN];
int x[MAXN];
int N, P, Q;
bool possible(int w) {
for (int i = 0; i <= N; i++) {
for (int j = 0; j <= Q; j++) {
dp[i][j] = -1;
}
}
dp[0][0] = P;
int lPI = 0;
int sPI = 0;
for (int i = 1; i <= N; i++) {
for (int nL = 0; nL <= Q; nL++) {
// case 1: use large
if (nL > 0) {
while (lPI + 1 <= N && x[lPI + 1] < x[i] - 2 * w + 1) {
lPI++;
}
dp[i][nL] = max(dp[i][nL], dp[lPI][nL - 1]);
}
// case 2: use small
while (sPI + 1 <= N && x[sPI + 1] < x[i] - w + 1) {
sPI++;
}
dp[i][nL] = max(dp[i][nL], dp[sPI][nL] - 1);
}
}
for (int nL = 0; nL <= Q; nL++) {
if (dp[N][nL] >= 0) {
return true;
}
}
return false;
}
int binSearch() {
int low = 1;
int hi = 1e9;
while (low != hi) {
assert(low < hi);
int mid = (low + hi) / 2;
if (possible(mid)) {
assert(hi != mid);
hi = mid;
} else {
low = mid + 1;
}
}
return low;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> N >> P >> Q;
P = min(P, N);
Q = min(Q, N);
x[0] = -2e9;
for (int i = 1; i <= N; i++) {
cin >> x[i];
}
sort(x, x + N + 1);
int ans = binSearch();
cout << ans << endl;
}
