#include <bits/stdc++.h>
#define ll unsigned long long
#define mod 998244353
#define rep(i,s) for(ll i=0; i<s ; i++)
#define f(i,a,b) for(ll i(a); i<b ; i++)
#define inf -pow(10,9)
#define MAXN 100000
const ll INF = 1000000000;
const ll N = 2005;
const ll modi = 1000000007;
const ll modi2= 1000000006;
using namespace std;
ll arr[N];
bool check(ll w , ll n, ll p , ll q){
ll dp[n + 1][p + 1];
rep(i,n){
ll l = 0;
ll r = 0;
while(arr[i] - arr[l] >= w){
l++;
}
while(arr[i] - arr[r] >= 2*w){
r++;
}
rep(j , p + 1){
if(j == 0){
if(r == 0){
dp[i][j] = 1;
}
else{
dp[i][j] = dp[r-1][j] + 1;
}
}
else{
if(l == 0){
dp[i][j] = 0;
}
else if(r == 0){
dp[i][j] = min(dp[l-1][j-1], (ll)1);
}
else{
dp[i][j] = min(dp[l-1][j-1], dp[r-1][j] + 1);
}
}
}
}
if(dp[n-1][p] <= q){
return true;
}
else{
return false;
}
}
int main(){
ll n,p,q;
cin >> n >> p >> q;
rep(i,n){
cin >> arr[i];
}
sort(arr,arr+n);
if(n <= p + q){
cout << 1 << endl;
}
else{
ll l = 1; ll r = 1000000010;
while(l < r){
ll mid = (l+r)/2;
if(check(mid,n,p,q)){
r = mid;
}
else{
l = mid + 1;
}
}
cout << l << endl;
}
}
