/**
* author: tuncypasha
* file: c.cpp
* created: 22.02.2026 10:26
**/
#include <bits/stdc++.h>
#define pasha ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(v) begin(v), end(v)
using namespace std;
// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
constexpr int N = 1e+7 + 5, oo = 1e+16;
void _() {
int n, p, q;
cin >> n >> p >> q;
vector<int> a(n);
for (int i = 0; i < n; ++i)
cin >> a[i];
sort(all(a));
int lo = 1, hi = 1e9, ans = 1e9;
while (lo <= hi) {
int mid = (lo + hi) >> 1;
int last = -1;
bool ok = true;
int cq = q, cp = p;
for (int i = 0; i < n; ++i) {
if (last >= a[i])
continue;
else {
if (p)
last = a[i] + mid - 1, --p;
else if (q)
last = a[i] + mid * 2 - 1, --q;
else {
ok = false;
break;
}
}
}
if (ok) {
ans = mid;
hi = mid - 1;
}
else lo = mid + 1;
p = cp, q = cq;
}
cout << ans << '\n';
}
signed main() {
pasha
int t = 1;
// cin >> t;
for (int cs = 1; cs <= t; ++cs) {
_();
// cout << '\n';
}
}
