#include <bits/stdc++.h>
#define int long long
#define all(a) a.begin(), a.end()
using namespace std;
const int inf = 1e18;
int n, p, q, go[2005][2005];
set <int> aa;
vector <int> a;
bool can(int mid){
// cout << mid << ": \n";
vector <vector <int>> dp(p + 1, vector <int> (q + 1));
for (int i = 0; i <= p; i++) {
for (int j = 0; j <= q; j++) {
if (i == 0 && j == 0) continue;
int pp = 0, qq = 0;
if (i > 0) pp = upper_bound(all(a), a[dp[i - 1][j]] + mid - 1) - a.begin();
if (j > 0) qq = upper_bound(all(a), a[dp[i][j - 1]] + mid + mid - 1) - a.begin();
dp[i][j] = max(pp, qq);
// cout << i << ", " << j << ": " << dp[i][j] << "\n";
}
}
// cout << "--------------\n";
return dp[p][q] >= a.size();
}
int32_t main(){
cin.tie(NULL)->sync_with_stdio(false);
cin >> n >> p >> q;
if (p > n) p = n;
if (q > n) q = n;
for (int i = 0; i < n; i++) {
int x; cin >> x;
aa.insert(x);
}
a = vector <int> (all(aa));
int l = 1, r = inf, ans = inf;
while (l <= r) {
int mid = (l + r) / 2;
if (can(mid)) {
r = mid - 1;
ans = mid;
}
else l = mid + 1;
}
cout << ans;
}
