#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <cassert>
#include <string>
#include <cstring>
#include <bitset>
#include <random>
#include <chrono>
#define FOR(i, a, b) for(int i = a; i < (int) b; i++)
#define F0R(i, a) FOR (i, 0, a)
#define ROF(i, a, b) for(int i = a; i >= (int) b; i--)
#define R0F(i, a) ROF(i, a, 0)
#define GO(i, a) for (auto i : a)
#define rsz resize
#define eb emplace_back
#define pb push_back
#define sz(x) (int) x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pii> vpii;
typedef vector<vi> vvi;
typedef vector<vpii> vvpii;
typedef long long i64;
typedef vector<i64> vi64;
typedef vector<vi64> vvi64;
typedef pair<i64, i64> pi64;
typedef vector<pi64> vpi64;
const int dr[] = {+1, -1, +0, +0, +1, -1, +1, -1};
const int dc[] = {+0, +0, +1, -1, +1, -1, -1, +1};
const int ms[] = {+31, +29, +31, 30, +31, +30, +31, +31, +30, +31, +30, +31};
const int N = 1e6 + 5;
int a [N], dp [N];
int main () {
ios::sync_with_stdio(0);
cin.tie(0);
int n, mn, mx;
cin >> n >> mn >> mx;
FOR (i, 1, n + 1) cin >> a[i];
sort (a, a + n + 1);
FOR (i, 1, N) dp[i] = 1e9;
dp[0] = 0;
int last_one = 0;
FOR (i, mn, n + 1) {
pair<int, int> best_way = {1e9, -1};
ROF (j, i - mn, max (last_one, i - mx)) {
pair<int, int> cur = { max (dp[j], a[i] - a[j + 1]), j };
best_way = min(best_way, cur);
dp[i] = min (dp[i], max (dp[j], a[i] - a[j + 1]));
if (a[i] - a[j + 1] >= dp[i]) break;
}
last_one = best_way.second;
}
cout << dp[n] << '\n';
return 0;
}
