/*
ID: varunra2
LANG: C++
TASK: watching
*/
#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#include "lib/debug.h"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define debug_arr(...) \
cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__)
#pragma GCC diagnostic ignored "-Wsign-compare"
//#pragma GCC diagnostic ignored "-Wunused-parameter"
//#pragma GCC diagnostic ignored "-Wunused-variable"
#else
#define debug(...) 42
#endif
#define EPS 1e-9
#define IN(A, B, C) assert(B <= A && A <= C)
#define INF (int)1e9
#define MEM(a, b) memset(a, (b), sizeof(a))
#define MOD 1000000007
#define MP make_pair
#define PB push_back
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define x first
#define y second
const double PI = acos(-1.0);
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef map<int, int> MPII;
typedef multiset<int> MSETI;
typedef set<int> SETI;
typedef set<string> SETS;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<string> VS;
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto& a : x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#pragma GCC diagnostic ignored "-Wsign-compare"
// util functions
int n, p, q;
VI vals;
VVI dp;
VVI to;
void init() {
vals.resize(n);
p = min(p, n);
q = min(q, n);
dp.resize(p + 1);
trav(x, dp) x.resize(q + 1);
to.resize(n + 1);
trav(x, to) x.resize(2);
}
bool works(int w, bool deb = false) {
if (p + q >= n) return true;
trav(x, dp) trav(y, x) y = 0;
trav(x, to) trav(y, x) y = 0;
for (int i = 0; i < n; i++) {
for (int j = 0; j < 2; j++) {
int too = vals[i] + (j + 1) * w;
int ind = lower_bound(all(vals), too) - vals.begin();
to[i][j] = ind;
}
}
for (int i = 0; i <= p; i++) {
for (int j = 0; j <= q; j++) {
if (dp[i][j] == n) {
return true;
}
if (i < p) {
int ind = to[dp[i][j]][0];
dp[i + 1][j] = max(dp[i + 1][j], ind);
}
if (j < q) {
int ind = to[dp[i][j]][1];
dp[i][j + 1] = max(dp[i][j + 1], ind);
}
}
}
return false;
}
int main() {
// #ifndef ONLINE_JUDGE
// freopen("watching.in", "r", stdin);
// freopen("watching.out", "w", stdout);
// #endif
cin.sync_with_stdio(0);
cin.tie(0);
cin >> n >> p >> q;
init();
trav(x, vals) cin >> x;
sort(all(vals));
int x = -1;
for (int b = INF; b >= 1; b /= 2) {
while (!works(x + b)) x += b;
}
cout << max(1, x + 1) << '\n';
return 0;
}
