#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ff(i,a,b) for(int i=a;i<=b;i++)
#define fb(i,b,a) for(int i=b;i>=a;i--)
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 2005;
const int inf = 1e9 + 5;
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
int n, p, q;
ll niz[maxn];
// p, q <= 1e5 i n <= 2000
// naive: n^2 * p * q
// za a malih kamera, koliko mi treba velikih da slikam prvih i proslova - dp[a][i]
// dp[a][i] <= q return 1, else return 0
int dp[maxn][maxn];
bool check(ll x){
int jp = 1;
int jq = 1;
memset(dp, 0, sizeof(dp));
ff(i,1,n){
while(niz[i] - niz[jp] >= x)jp += 1;
while(niz[i] - niz[jq] >= 2 * x)jq += 1;
ff(j,0,p){
if(j != 0){
// ili uradim sa malom kamerom [jp, i]
// ili uradim sa velikom kamerom [jq, i], ali dodam jedan
dp[i][j] = min(dp[jp - 1][j - 1], dp[jq - 1][j] + 1);
}
else dp[i][j] = dp[jq - 1][j] + 1;
}
}
int mn = inf;
ff(j,0,p)mn = min(mn, dp[n][j]);
return mn <= q;
}
int main()
{
ios::sync_with_stdio(false);
cout.tie(nullptr);
cin.tie(nullptr);
cin >> n >> p >> q;
ff(i,1,n)cin >> niz[i];
if(p + q >= n)return cout << 1, 0;
sort(niz + 1, niz + n + 1);
int l = 1, r = inf, ans = inf;
while(l <= r){
int mid = (l + r) / 2;
if(check(mid)){
ans = mid;
r = mid - 1;
}
else l = mid + 1;
}
cout << ans << endl;
return 0;
}
/**
3 1 1
2
11
17
// probati bojenje sahovski ili slicno
**/
