#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair < int, int > PII;
#define F first
#define S second
#define mkp make_pair
#define eb emplace_back
#define all(a) a.begin(), a.end()
#define sz(a) (int)a.size()
#define forn(x, a, b) for (int x = a; x <= b; ++x)
#define for1(x, a, b) for (int x = a; x >= b; --x)
const ll ool = 1e18 + 9;
const int N = 3e3 + 3, oo = 1e9 + 9;
int n, P, Q, a[N], d[N][N];
bool check(int W) {
int ptr = 1;
forn(i, 0, P) forn(j, 0, Q) d[i][j] = 1;
forn(i, 0, P) {
forn(j, 0, Q) {
if (d[i][j] == -1) continue;
int ptr = d[i][j];
while (ptr <= n && a[ptr] - a[d[i][j]] + 1 <= W) {
++ptr;
}
d[i + 1][j] = max(d[i + 1][j], ptr);
while (ptr <= n && a[ptr] - a[d[i][j]] + 1 <= 2 * W) {
++ptr;
}
d[i][j + 1] = max(d[i][j + 1], ptr);
}
}
return (d[P][Q] == n + 1);
}
int main() {
#ifdef krauch
freopen("input.txt", "r", stdin);
#endif
cin >> n >> P >> Q;
Q = min(Q, n);
P = min(P, n - Q);
forn(i, 1, n) {
cin >> a[i];
}
sort(a + 1, a + n + 1);
int l = 1, r = a[n];
while (l < r) {
int mid = (l + r) >> 1;
if (check(mid)) r = mid;
else l = mid + 1;
}
cout << l << "\n";
return 0;
}
