#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, q;
  cin >> n >> k >> q;
  vector<int> a(n);
  vector<int> o(n);
  for (int i = 0; i < n; i++) {
    cin >> a.at(i);
    o.at(i) = a.at(i);
  }
  a.push_back(0);
  sort(o.begin(), o.end());
  int m;
  for (int x = 0; x < n; x++) {
    vector<vector<int>> c(x + 1);
    for (int i = 0, p = 0; i <= n; i++) {
      if (a.at(i) == 0) {
        sort(c.at(p).begin(), c.at(p).end());
        p++;
      } else
        c.at(p).push_back(a.at(i));
    }
    vector<int> ch;
    for (auto x : c)
      for (int i = 0; i < max((int)x.size() - k + 1, 0); i++)
        ch.push_back(x.at(i));
    if (ch.size() < q) break;
    sort(ch.begin(), ch.end());
    m = (x == 0 ? ch.at(q - 1) - ch.at(0) : min(m, ch.at(q - 1) - ch.at(0)));
    for (int i = 0; i <= n; i++) {
      if (a.at(i) == a.at(x)) {
        a.at(i) = 0;
        break;
      }
    }
  }
  cout << m << endl;
}
