#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define fst first
#define snd second
#define int long long
#define MMAX 16384
#define fast_io() ios::sync_with_stdio(false)
#define FOR(i, l, r) for(int i = (l); i < (r); i++)
typedef long long ll;
typedef pair<ll, ll> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef set<int> si;
typedef double ld;
typedef pair<ld, ld> dd;
const ll INF = 1000000000000000000LL;
const int NMAX = 2e3+4;
const int mod = 1e9+7;
const ld eps = 1e-10;
const ld PI = acos(-1);
int w, N, P, Q;
vi A;
int dp[NMAX][NMAX];
int leastQ(int i, int p){
//cout << i << " " << p << endl;
if(p < 0) return INF;
int &res = dp[i][p];
if(res != -1) return res;
if(i == N) return res = 0;
res = INF;
res = min(res, leastQ(upper_bound(A.begin(), A.end(), A[i]+ w-1) - A.begin(), p-1));
res = min(res, 1 + leastQ(upper_bound(A.begin(), A.end(), A[i]+2*w-1) - A.begin(), p ));
return res;
}
signed main(){
fast_io();
cin >> N >> P >> Q;
A.resize(N);
FOR(i, 0, N) cin >> A[i];
sort(A.begin(), A.end());
if(P+Q >= N) {
cout << 1 << endl;
return 0;
}
int lb = 0, rb = 1e9;
while(lb+1 != rb){
FOR(i, 0, NMAX) FOR(j, 0, NMAX) dp[i][j] = -1;
w = (lb+rb)/2;
if(leastQ(0, P) <= Q) rb = w;
else lb = w;
}
cout << rb << endl;
}
