#include <bits/stdc++.h>
#define int long long int
#define ff first
#define ss second
const int MOD = 1000000007;
using namespace std;
const int N = 200005;
void solve(){
int n, x, y;
cin >> n >> x >> y;
vector<int> a;
for(int i = 0; i < n; i++){
int b;
cin >> b;
a.push_back(b);
}
sort(a.begin(), a.end());
int dp[n+1][n+1];
x = min(x, n);
int l = 1, r = 1e9;
while(l != r){
int w = (l + r)/2;
for(int i = 0; i <= n; i++) for(int j = 0; j <= n; j++) dp[i][j] = -1;
dp[0][x] = y;
for(int i = 0; i < n; i++){
for(int j = 0; j <= x; j++){
int k = dp[i][j];
if(k == -1) continue;
if(j != 0){
int p = upper_bound(a.begin(), a.end(), a[i]+w-1) - a.begin();
dp[p][j-1] = max(dp[p][j-1], k);
// cout << w << " " << i << " " << j << " kısa " << p << endl;
}
if(k != 0){
int p = upper_bound(a.begin(), a.end(), a[i]+2*w-1) - a.begin();
dp[p][j] = max(dp[p][j], k-1);
// cout << w << " " << i << " " << j << " uzun " << p << endl;
}
}
}
int ok = 0;
for(int j = 0; j < x; j++) if(dp[n][j] != -1) ok = 1;
// cout << w << " " << ok << endl;
if(ok) r = w;
else l = w+1;
}
cout << l << endl;
}
int32_t main(){
int t;
t = 1;
while(t--) solve();
}
