#include "bits/stdc++.h"
using namespace std;
using i64 = long long;
using u64 = unsigned long long;
using i32 = int;
using u32 = unsigned;
using i16 = short;
using u16 = unsigned short;
using ld = long double;
using ii = pair<int, int>;
const int inf = 1e9, N = 2e3 + 100;
int n, p, q;
array<int, N> dp[2];
vector<int> a;
bool f(int w) {
for(int i = 0; i <= n; ++i) dp[0][i] = -inf;
dp[0][0] = 0;
for(int i = 1; i <= p + q; ++i) {
int hi[2] = {0};
for(int i = 0; i <= n; ++i) dp[1][i] = -inf;
for(int k = 0; k < n; ++k) {
while(hi[0] < n && a[hi[0]] - a[k] < w) ++hi[0];
while(hi[1] < n && a[hi[1]] - a[k] < 2 * w) ++hi[1];
dp[1][hi[0]] = max(dp[1][hi[0]], dp[0][k] + 1);
dp[1][hi[1]] = max(dp[1][hi[1]], dp[0][k]);
}
swap(dp[0], dp[1]);
if(dp[0][n] >= p || i - dp[0][n] <= q) return true;
}
return false;
}
void solve() {
cin >> n >> p >> q;
a.resize(n);
for(int i = 0; i < n; ++i) cin >> a[i];
if(p + q >= n) {
cout << "1\n";
return;
}
sort(a.begin(), a.end());
vector<int> d;
for(int i = 0; i < n; ++i) {
for(int j = i + 1; j < n; ++j) {
d.push_back(a[j] - a[i] + 1);
d.push_back((a[j] - a[i] + 2) / 2);
}
}
sort(d.begin(), d.end());
d.resize(unique(d.begin(), d.end()) - d.begin());
int lo = 0, hi = (int)d.size() - 1;
while(lo < hi) {
int mid = (lo + hi) / 2;
if(f(d[mid])) hi = mid;
else lo = mid + 1;
}
cout << d[hi] << '\n';
}
int main() {
ios_base :: sync_with_stdio(false);
cin.tie(0);
int t = 1;
//cin >> t;
while(t--) solve();
return 0;
}
