#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " <<
#define all(cont) cont.begin(),cont.end()
#define vi vector<int>
const int inf = 1e17,N = 2e6+1,MOD = 998244353,B = 600;
array<array<int,2001>,2001> dp;
void solve() {
int n,p,q;
cin >> n >> p >> q;
vi a(n+1);
for (int i=1;i<=n;i++) cin >> a[i];
sort(a.begin()+1,a.end());
p = min(p,n);
q = min(q,n);
vi coverp(n+1),coverq(n+1);
queue<int> dq;
auto check = [&](int w) -> bool {
for (int i = 0;i<=n;i++) for (int j = 0;j<=p;j++) dp[i][j] = inf;
while (!dq.empty()) dq.pop();
for (int i = n;i >= 1;i--) {
while (!dq.empty() && a[dq.front()] > a[i]+w-1) dq.pop();
dq.push(i);
coverp[i] = dq.front();
}
while (!dq.empty()) dq.pop();
for (int i = n;i >= 1;i--) {
while (!dq.empty() && a[dq.front()] > a[i]+2*w-1) dq.pop();
dq.push(i);
coverq[i] = dq.front();
}
dp[0][0] = 0;
for (int i = 0;i<n;i++) {
for (int j = 0;j<=p;j++) {
if (dp[i][j] == inf) continue;
dp[coverp[i+1]][j+1] = min(dp[coverp[i+1]][j+1],dp[i][j]);
dp[coverq[i+1]][j] = min(dp[coverq[i+1]][j],dp[i][j]+1);
}
}
for (int i=0;i<=p;i++) if (dp[n][i] <= q) return 1;
return 0;
};
int l = 1;
int r = 1e9;
while (l<=r) {
int w = (l+r) >> 1;
if (check(w)) r = w-1;
else l = w+1;
}
cout << l << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#ifdef Dodi
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t = 1;
//cin >> t;
while (t --> 0) solve();
}
