#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ld long double
#define MOD 998244353
ll n, p, q, s = 1, e = 1e9 + 5, ans = 1e9 + 5;
ll dp[2005][2005], a[2005];
bool c(ll x)
{
for (ll i = 1; i <= n; i++)
{
ll l = 1, r = 1;
while (a[i] - a[l] >= x)
{
l++;
}
while (a[i] - a[r] >= 2 * x)
{
r++;
}
for (ll j = 0; j <= p; j++)
{
if (j == 0)
{
dp[i][j] = dp[r - 1][j] + 1;
}
else
{
dp[i][j] = min(dp[l - 1][j - 1], dp[r - 1][j] + 1);
}
}
}
return dp[n][p] <= q;
}
void solve()
{
cin >> n >> p >> q;
for (int i = 1; i <= n; i++)
{
cin >> a[i];
}
if (p + q >= n)
{
cout << 1 << '\n';
exit(0);
}
sort(a + 1, a + n + 1);
while (s <= e)
{
ll m = (s + e) / 2;
memset(dp, 0, sizeof(dp));
if (c(m))
{
ans = m;
e = m - 1;
}
else
{
s = m + 1;
}
}
cout << ans << '\n';
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll t = 1;
// cin >> t;
// cout << fixed << setprecision(12);
for (ll i = 1; i <= t; i++)
{
solve();
}
}
