#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define endl '\n';
#define fastio ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define py cout << "YES" << endl;
#define pn cout << "NO" << endl;
#define pb push_back
#define int long long
typedef long double lld;
#define double lld
typedef long long ll;
typedef unsigned long long ull;
const ll inf = 1e18;
const ll mod = 1e9+7;
const int N = 2e5;
vector<int>primes = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97};
// Check for queue, priorioty_queue, stack, ordered_set solutions
// stack => LIFO (whatever goes in last comes out last)
// queue => FIFO (whatever goes in first comes out first)
// priority_queue => Dynamic queries of minimum/maximum
// ordered_set => set in vector form
//[order_of_key(k) gives number of elements less than k, while find_by_order(i) gives i^th element]
// To comment multiple lines : ctrl + /
// To find and replace : ctrl+H
void judge(){
srand(time(NULL));
#ifndef ONLINE_JUDGE
freopen("1.txt","r",stdin);
freopen("2.txt","w",stdout);
freopen("Error.txt", "w", stderr);
#define debug(x...) cerr << #x <<" = "; _print(x); cerr << endl;
#else
#define debug(x...)
#endif
}
void usaco(string s) {
freopen((s + ".in").c_str(),"r",stdin);
freopen((s + ".out").c_str(),"w",stdout);
}
signed main(){
fastio; //judge();
int n,p,q; cin >> n >> p >> q;
vector<int>a(n);
for(auto &x : a) cin >> x;
sort(a.begin(),a.end());
if((p+q)>=n){
cout << 1; return 0;
}
auto f1 = [&](int x){
vector<vector<int>>dp(n,vector<int>(p+1));
for(int i = n-1;i>=0;i--){
auto it = upper_bound(a.begin(),a.end(),a[i]+2*x-1);
if(it==a.end()){
for(int j = 0;j<=p;j++){
dp[i][j] = 1;
}
}
else{
for(int j = 0;j<=p;j++){
dp[i][j] = 1 + dp[it-a.begin()][j];
}
}
for(int j = 1;j<=p;j++){
auto it = upper_bound(a.begin(),a.end(),a[i]+x-1);
if(it==a.end()){
dp[i][j] = 0;
}
else{
dp[i][j] = min(dp[i][j],dp[it-a.begin()][j-1]);
}
}
}
return (dp[0][p] <= q);
};
auto f2 = [&](int x){
swap(p,q);
vector<vector<int>>dp(n,vector<int>(p+1));
for(int i = n-1;i>=0;i--){
auto it = upper_bound(a.begin(),a.end(),a[i]+x-1);
if(it==a.end()){
for(int j = 0;j<=p;j++){
dp[i][j] = 1;
}
}
else{
for(int j = 0;j<=p;j++){
dp[i][j] = 1 + dp[it-a.begin()][j];
}
}
for(int j = 1;j<=p;j++){
auto it = upper_bound(a.begin(),a.end(),a[i]+2*x-1);
if(it==a.end()){
dp[i][j] = 0;
}
else{
dp[i][j] = min(dp[i][j],dp[it-a.begin()][j-1]);
}
}
}
return (dp[0][p] <= q);
};
int low = 1, high = 1e9, ans = inf;
while(low<=high){
int mid = (low+high)/2;
if(p<=q){
if(f1(mid)){
ans = mid, high = mid-1;
}
else{
low = mid+1;
}
}
else{
if(f2(mid)){
ans = mid, high = mid-1;
}
else{
low = mid+1;
}
}
}
cout << ans;
}
