#include <bits/stdc++.h>
using namespace std;
#define int long long
#define inf 0x3F3F3F3F
const int MXN = 2e3 + 5;
int n, p, q;
int a[MXN];
int dp[MXN][MXN];
int need(int val)
{
for (int i = 0; i <= p; i++)
{
int k1 = 0, k2 = 0;
for (int j = 1; j <= n; j++)
{
dp[i][j] = inf;
while (k1 + 1 <= n && a[k1 + 1] <= a[j] - val) k1++;
while (k2 + 1 <= n && a[k2 + 1] <= a[j] - 2 * val) k2++;
dp[i][j] = dp[i][k2] + 1;
if (i) dp[i][j] = min(dp[i][j], dp[i - 1][k1]);
}
}
return dp[p][n];
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> p >> q;
if (p >= n || q >= n)
{
cout << 1 << '\n';
return 0;
}
p = min(p, n), q = min(q, n);
for (int i = 1; i <= n; i++) cin >> a[i];
sort(a + 1, a + n + 1);
int l = 1, r = 1e9;
while (l < r)
{
int mid = (l + r) >> 1;
if (need(mid) > q) l = mid + 1;
else r = mid;
}
cout << l << '\n';
}
