#include <iostream>
#include <iomanip>
#include <random>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <numeric>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <sstream>
#include <bitset>
#include <cassert>
#include <fstream>
#include <queue>

#define len(X) ((int)(X).size())

#ifdef __LOCAL
	#define DEBUG_OUTPUT_ENABLED 1
	#define DBG(X) dout << #X << "=" << (X) << '\n';
	#define SAY(X) dout << (X) << '\n';
#else
	#define DEBUG_OUTPUT_ENABLED 0
	#define DBG(X) 42;
	#define SAY(X) 42;
#endif

#define dout   debug::instance

using namespace std;

template<typename T, typename S> inline ostream& operator<<(ostream& os, const pair<T, S> p) { cout << "[" << p.first << ";" << p.second << "]"; return os; }
template<typename T> inline ostream& operator<<(ostream& os, const vector<T>& v) { for(auto el: v) cout << el << " "; return os; }
namespace debug {
	struct DebugStream {
		private:
			bool is_first;
		public:
			DebugStream(bool _is_first): is_first(_is_first) {}
			template<typename T> DebugStream operator<<(const T& value) const {
				assert(DEBUG_OUTPUT_ENABLED);
				if(is_first) cout << "[DBG] ";
				cout << value;
				return DebugStream(false);
			};

			template<typename T> DebugStream printArray(T* l, T* r) {
				assert(DEBUG_OUTPUT_ENABLED);
				if(is_first) cout << "[DBG] ";
				while(l != r) {
					cout << (*l);
					++l;
					if(l == r) {
						cout << '\n';
					} else {
						cout << ' ';
					}
				}
				return DebugStream(false);
			}
	};
	DebugStream instance(true);
};

using ll = long long int;
using ull = unsigned long long int;
using ld  = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int INT_INF = (int)(2e9);
const ll  LL_INF  = (ll)(2e18);

const int NIL = -1;
static mt19937 _g(time(nullptr));

inline ll randint(ll a, ll b) { ll w = (_g() << 31LL) ^ _g(); return a + w % (b - a + 1); }
inline void fast_io() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); };
template<typename T> inline T sign(T x) { return T(x > 0) - T(x < 0); }
template<typename T> inline T fetch() { T ret; cin >> ret; return ret; }
template<typename T> inline vector<T> fetch_vec(int sz) { vector<T> ret(sz); for(auto& elem: ret) cin >> elem; return ret; }
const int MAXN = 2007;
int a[MAXN], ord[MAXN], n, k, q, answ = INT_INF;
int check(int low, int high) {
	int ops = 0;
	set<pii> byVal, byPos;
	int ptr = 0;
	while(ptr < n) {
		byVal.emplace(a[ptr], ptr);
		byPos.emplace(ptr, a[ptr]);
		if(len(byVal) > k) {
			int p = (byPos.begin())->first;
			byVal.erase(make_pair(a[p], p));
			byPos.erase(make_pair(p, a[p]));
		}
		if(len(byVal) >= k) {
			auto iter = byVal.begin();
			if(iter->first >= low && iter->first <= high) {
				++ops;
				int p = iter->second;
				byVal.erase(make_pair(a[p], p));
				byPos.erase(make_pair(p, a[p]));
			}
		}
		++ptr;
	}
	return ops >= q;
}
void solve() {
	cin >> n >> k >> q; for(int i = 0; i < n; ++i) a[i] = ord[i] = fetch<int>();
	sort(ord, ord + n);
	int r = 0;
	for(int l = 0; l < n; ++l) {
		if(r < l) r = l;
		while(r < n && !check(ord[l], ord[r])) ++r;
		if(r < n) answ = min(answ, ord[r] - ord[l]);
	}
	cout << answ << '\n';
}

int main() {
	fast_io();
	solve();

	return 0;
}


Measured memory_bytes: 512