#include <bits/stdc++.h>
#define endl '\n'
#define int long long
#define fi first
#define se second
#define pb push_back
using namespace std;
bool check(int n, int p, int q, vector<int> a, int w){
vector<vector<int>> dp(n+5, vector<int>(p+5, 0));
dp[0][0] = 1;
for (int i = 1; i < n; i++){
int lastSmall = 0, lastBig = 0;
for (int j = 0; j <= i; j++){
if (a[i] - a[j] >= w){
lastSmall++;
}
else{
break;
}
}
for (int j = 0; j <= i; j++){
if (a[i] - a[j] >= 2*w){
lastBig++;
}
else{
break;
}
}
// no small cams, forced to use big
dp[i][0] = (lastBig == 0 ? 1LL : dp[lastBig-1][0] + 1LL);
for (int j = 1; j <= p; j++){
if (lastSmall == 0){
// place 1 small camera, will definitely have 1 small cam availible => 0 large cams
dp[i][j] = 0LL;
}
else if (lastBig == 0){
// either use 1 large camera or use 1 small cam
dp[i][j] = min(dp[lastSmall-1][j-1], 1LL);
}
else dp[i][j] = min(dp[lastSmall-1][j-1], dp[lastBig-1][j] + 1);
}
}
int ans = 100000000;
for (int i = 0; i <= p; i++){
ans = min(ans, dp[n-1][i]);
}
return ans <= q;
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
while(t--){
// p - small, q - large
int n, p, q;
cin >> n >> p >> q;
vector<int> a(n);
for (int i = 0; i < n; i++){
cin >> a[i];
}
sort(a.begin(), a.end());
if (p + q >= n){
cout << 1;
break;
}
int l = 1, r = 1000000001;
while(l < r){
int mid = (l + r) / 2;
if (check(n, p, q, a, mid)){
r = mid;
}
else{
l = mid + 1;
}
}
cout << r;
}
}
