// 道草を楽しめ 大いにな。ほしいものより大切なものが きっとそっちに ころがってる
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
using u128 = __uint128_t; // available on 64-bit targets
//defines
#define int long long
#define debug(x) cerr << "(" << #x << "=" << x << "," << __LINE__ << ")\n";
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rep(i,a,b) for(int i=a;i<(b);i++)
#define fastio() ios_base::sync_with_stdio(false);cin.tie(NULL);
//constants
const int dx[4]{1, 0, -1, 0}, dy[4]{0, 1, 0, -1};
const char dir[4]{'D','R','U','L'};
const int maxn=2e5+5;
const double eps=1e-9;
//typedefs
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<string> vs;
//Template
template<class T> using oset=tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
template <typename T, auto M> struct Mod {
using V = conditional_t<sizeof(T) <= 4, u64, u128>;
static V inv(V x, V m) { return x > 1 ? m - inv(m % x, x) * m / x : 1; }
make_unsigned_t<T> x;
Mod() : x(0) {}
Mod(auto y) : x(y % M) { x >= M ? x += M : x; }
operator T() const { return x; }
Mod operator-() const { return Mod() -= *this; }
Mod operator+(auto rhs) const { return Mod(*this) += rhs; }
Mod operator-(auto rhs) const { return Mod(*this) -= rhs; }
Mod operator*(auto rhs) const { return Mod(*this) *= rhs; }
Mod operator/(auto rhs) const { return Mod(*this) /= rhs; }
Mod &operator+=(Mod rhs) { return (x += rhs.x) >= M ? x -= M : x, *this; }
Mod &operator-=(Mod rhs) { return (x -= rhs.x) >= M ? x += M : x, *this; }
Mod &operator*=(Mod rhs) { return x = x * V(rhs.x) % M, *this; }
Mod &operator/=(Mod rhs) { return x = x * inv(rhs.x, M) % M, *this; }
Mod pow(auto y) const { // O(log y) | 0^(-inf,0] -> 1
Mod ans(1), base(*this);
for (auto e = y < 0 ? ~y + u128(1) : +y; e; e >>= 1, base *= base) {
e & 1 ? ans *= base : ans;
}
return y < 0 ? Mod(1) /= ans : ans;
}
};
using mint = Mod<int, 998244353>;
void solve()
{
int n,p,q;
cin >> n >> p >> q;
vector<int> a(n);
for(int i=0;i<n;i++)
{
cin >> a[i];
}
p=min(p,n);
q=min(q,n);
sort(all(a));
int l=0,r=1e9,ans=1e9;
while(l<=r)
{
int mid=(l+r)/2;
vector<vector<int>> dp(n+1,vector<int>(p+1,1e12));
dp[0][0]=0;
for(int i=0;i<n;i++)
{
for(int j=0;j<=p;j++)
{
if(dp[i][j]>q)
{
continue;
}
//use small camera
int next=lower_bound(all(a),a[i]+mid)-a.begin();
if(j+1<=p)
{
dp[next][j+1]=min(dp[next][j+1],dp[i][j]);
}
// use big
next=lower_bound(all(a),a[i]+2*mid)-a.begin();
dp[next][j]=min(dp[next][j],dp[i][j]+1);
}
}
bool flag=0;
for(int i=0;i<=p;i++)
{
if(dp[n][i]<=q)
{
flag=1;
break;
}
}
if(flag)
{
ans=mid;
r=mid-1;
}
else
{
l=mid+1;
}
}
cout << ans << '\n';
}
signed main()
{
fastio();
int t=1;
// cin >> t;
while(t--)
{
solve();
}
return 0;
}
