#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void chmax(T& a, T b) {
  a = std::max(a, b);
}
template <class T>
inline void chmin(T& a, T b) {
  a = std::min(a, b);
}
bool prime(long long x) {
  for (long long i = 2; i * i <= x; i++) {
    if (x % i == 0) return false;
  }
  return x != 1;
}
long long gcd(long long x, long long y) {
  if (y == 0) return x;
  return gcd(y, x % y);
}
long long lcm(long long x, long long y) { return x / gcd(x, y) * y; }
long long kai(long long x, long long y) {
  long long res = 1;
  for (long long i = x - y + 1; i <= x; i++) {
    res *= i;
    res %= (long long)(1e9 + 7);
  }
  return res;
}
long long mod_pow(long long x, long long y, long long m) {
  long long res = 1;
  while (y > 0) {
    if (y & 1) {
      res = res * x % m;
    }
    x = x * x % m;
    y >>= 1;
  }
  return res;
}
long long comb(long long x, long long y) {
  if (y > x) return 0;
  return kai(x, y) *
         mod_pow(kai(y, y), (long long)(1e9 + 7) - 2, (long long)(1e9 + 7)) %
         (long long)(1e9 + 7);
}
long long get_rand(long long MIN, long long MAX) {
  std::random_device rnd;
  std::mt19937 mt32(rnd());
  std::uniform_int_distribution<long long> engine(MIN, MAX);
  return engine(mt32);
}
long long n, k, q;
long long a[2005];
bool ng[2005];
std::pair<long long, long long> p[2005];
signed main() {
  cin >> n >> k >> q;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    p[i] = {a[i], i};
  }
  sort(a, a + n);
  long long ans = (long long)(3e18);
  vector<long long> ngs = {-1, n};
  for (long long i = 0; i < n + 1; i++) {
    vector<long long> v;
    for (long long j = 0; j < ngs.size() - 1; j++) {
      if (ngs[j + 1] - ngs[j] - 1 < k) continue;
      vector<long long> v2;
      for (long long l = ngs[j] + 1; l < ngs[j + 1]; l++) v2.push_back(a[l]);
      sort(v2.begin(), v2.end());
      for (long long l = 0; l < (ngs[j + 1] - ngs[j]) - k; l++) {
        v.push_back(v2[l]);
      }
    }
    if (v.size() < q) break;
    sort(v.begin(), v.end());
    chmin(ans, v[q - 1] - v[0]);
    ngs.push_back({p[i].second});
    sort(ngs.begin(), ngs.end());
  }
  cout << ans << endl;
}
