#include <bits/stdc++.h>
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(0);
    if (is_first) cout << "[DBG] ";
    cout << value;
    return DebugStream(false);
  };
  template <typename T>
  DebugStream printArray(T* l, T* r) {
    assert(0);
    if (is_first) cout << "[DBG] ";
    while (l != r) {
      cout << (*l);
      ++l;
      if (l == r) {
        cout << '\n';
      } else {
        cout << ' ';
      }
    }
    return DebugStream(false);
  }
};
DebugStream instance(true);
};  // namespace debug
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;
  multiset<int> cur;
  int ptr = 0;
  while (ptr < n) {
    cur.insert(a[ptr]);
    if (((int)(cur).size()) > k) {
      auto iter = cur.find(a[ptr - k]);
      if (iter != cur.end()) cur.erase(iter);
    }
    if (((int)(cur).size()) >= k) {
      auto iter = cur.begin();
      if (*iter >= low && *iter <= high) {
        ++ops;
        cur.erase(iter);
      }
    }
    ++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;
}
