#include <bits/stdc++.h>
const int MOD = 1e9 + 7;
const int iINF = 2147483647 / 2;
const long long int llINF = 9223372036854775807 / 2;
using namespace std;
using ll = long long int;
using vl = vector<ll>;
using vvl = vector<vector<ll>>;
using vvvl = vector<vector<vector<ll>>>;
bool paircomp(const pair<ll, ll> &a, const pair<ll, ll> &b) {
  if (a.first == b.first) return a.second < b.second;
  return a.first < b.first;
}
ll POW(ll n, ll m) {
  if (m == 0) {
    return 1;
  } else if (m % 2 == 0) {
    ll tmp = POW(n, m / 2);
    return (tmp * tmp);
  } else {
    return (n * POW(n, m - 1));
  }
}
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ll N, K, Q;
  cin >> N >> K >> Q;
  vector<pair<ll, ll>> A(N);
  vl B;
  for (ll i = 0; i < (N); i++) {
    ll a;
    cin >> a;
    A[i] = make_pair(a, i);
  }
  sort((A).begin(), (A).end());
  ll ans = A[Q - 1].first - A[0].first;
  for (ll i = 0; i < (N - Q); i++) {
    B.push_back(A[i].second);
    ll count = 0;
    ll now = -1;
    for (ll j = 0; j < (i + 1); j++) {
      count += max(B[j] - now - 1 - K + 1, 0LL);
      now = B[j];
    }
    count += max(N - now - K + 1, 0LL);
    if (count < Q) {
      break;
    } else {
      ans = min(ans, A[Q + i].first - A[i + 1].first);
    }
  }
  cout << ans << endl;
  return 0;
}
