#include<bits/stdc++.h>
#define fi first
#define se second
#define int long long
using namespace std;
using ll = long long;
using ii = pair<int, int>;
using aa = array<int,3>;
const int N = 2005;
int n, p, q, ans;
int a[N], dp[N][N];
bool ok(int mid){
dp[0][0] = 0;
for (int used = 0; used <= min(n,p); used++){
int sid = 1;
int lid = 1;
for (int i = 1; i <= n; i++){
dp[i][used] = 1e9;
while (sid <= n && a[sid] <= a[i] - mid){
sid++;
}
while (lid <= n && a[lid] <= a[i] - mid * 2){
lid++;
}
if (used == 0) dp[i][used] = dp[lid - 1][used] + 1;
else{
dp[i][used] = min({dp[lid - 1][used] + 1,dp[sid - 1][used - 1]});
}
}
}
for (int i = 0; i <= min(n,p); i++){
if (dp[n][i] <= q) return 1;
}
return 0;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
cin >> n >> p >> q;
for (int i = 1; i <= n; i++) cin >> a[i];
sort(a+1,a+1+n);
int l = 1, r = (int)1e9;
while (l <= r){
int mid = (l + r) >> 1;
if (ok(mid)){
ans = mid;
r = mid - 1;
} else l = mid + 1;
}
cout << ans;
return 0;
}
