#include <bits/stdc++.h>
using namespace std;
using ll = long long;
void debug_out() { std::cout << std::endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cout << H << " ";
  debug_out(T...);
}
template <typename T>
std::ostream& operator<<(std::ostream& os, std::vector<T> vec) {
  for (std::size_t i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  return os;
}
struct Edge {
  int to;
  ll weight;
  Edge(int t, ll w) : to(t), weight(w) {}
};
struct edge {
  int from;
  int to;
  ll weight;
  edge(int f, int t, ll w) : from(f), to(t), weight(w) {}
};
using Graph = vector<vector<Edge>>;
using graph = vector<vector<int>>;
using edges = vector<edge>;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
T lcm(T a, T b) {
  return (a * b) / gcd(a, b);
}
ll ctoi(char c) {
  switch (c) {
    case '0':
      return 0;
    case '1':
      return 1;
    case '2':
      return 2;
    case '3':
      return 3;
    case '4':
      return 4;
    case '5':
      return 5;
    case '6':
      return 6;
    case '7':
      return 7;
    case '8':
      return 8;
    case '9':
      return 9;
    default:
      return 0;
  }
}
constexpr ll LNF = 1LL << 50;
constexpr int INF = 1e9 + 7;
const long double PI = 3.14159265358979323846;
vector<int> dx = {-1, 0, 1, 0, -1, 1, -1, 1};
vector<int> dy = {0, -1, 0, 1, 1, -1, -1, 1};
int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n, k, q;
  cin >> n >> k >> q;
  vector<ll> a(n);
  for (int i = (int)(0); i < (int)(n); i++) cin >> a[i];
  ll ans = LNF;
  for (int i = (int)(0); i < (int)(n); i++) {
    ll m = 0;
    priority_queue<ll, vector<ll>, greater<ll>> que;
    vector<ll> tmp;
    for (int j = (int)(0); j < (int)(n); j++) {
      if (i == j) continue;
      if (a[i] <= a[j]) {
        que.push(a[j]);
      } else {
        while (que.size() >= k) {
          tmp.emplace_back(que.top());
          que.pop();
        }
        priority_queue<ll, vector<ll>, greater<ll>> emp;
        que.swap(emp);
      }
    }
    while (que.size() >= k) {
      tmp.emplace_back(que.top());
      que.pop();
    };
    if (tmp.size() < q - 1) {
      continue;
    }
    sort((tmp).begin(), (tmp).end());
    chmin(ans, tmp[q - 2] - a[i]);
  }
  cout << ans << endl;
}
