#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
template <class T>
using vec = vector<T>;
template <class T>
using vvec = vector<vec<T>>;
constexpr long long INF = 1LL << 60;
constexpr int INF_INT = 1 << 25;
constexpr long long MOD = (ll)1e9 + 7;
using ld = long double;
static const ld pi = 3.141592653589793L;
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;
}
struct Edge {
  ll to, rev;
  long double cap;
  Edge(ll _to, long double _cap, ll _rev) {
    to = _to;
    cap = _cap;
    rev = _rev;
  }
};
using Edges = vector<Edge>;
using Graph = vector<Edges>;
void add_edge(Graph &G, ll from, ll to, long double cap, bool revFlag,
              long double revCap) {
  G[from].push_back(Edge(to, cap, (ll)G[to].size()));
  if (revFlag) G[to].push_back(Edge(from, revCap, (ll)G[from].size() - 1));
}
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
class UnionFind {
  vector<int> data;
  int num;

 public:
  UnionFind(int size) : data(size, -1), num(size) {}
  bool unionSet(int x, int y) {
    x = root(x);
    y = root(y);
    if (x != y) {
      if (data[y] < data[x]) swap(x, y);
      data[x] += data[y];
      data[y] = x;
      num--;
    }
    return x != y;
  }
  bool findSet(int x, int y) { return root(x) == root(y); }
  int root(int x) { return data[x] < 0 ? x : data[x] = root(data[x]); }
  int size(int x) { return -data[root(x)]; }
  int numSet() { return num; }
};
void solve() {
  ll n, k, q;
  cin >> n >> k >> q;
  vec<ll> a(n);
  for (int(i) = (int)(0); i < (int)(n); ++i) cin >> a[i];
  vec<pair<ll, ll>> b(n);
  for (int(i) = (int)(0); i < (int)(n); ++i) b[i] = {a[i], i};
  sort((b).begin(), (b).end());
  ll ans = b[q - 1].first - b[0].first;
  vec<bool> used(n, false);
  multiset<ll> h;
  vec<multiset<ll>> s(n);
  UnionFind uni(n);
  multiset<ll> nh;
  auto merge_s = [&](int x, int y) {
    uni.unionSet(x, y);
    int r = uni.root(x);
    if (r == y) swap(x, y);
    for (auto i : s[y]) {
      s[x].insert(i);
    }
    s[y].clear();
    while (s[x].size() >= k) {
      auto it = s[x].begin();
      nh.insert(*it);
      s[x].erase(it);
    }
  };
  for (int(i) = (int)(n)-1; i >= (int)(0); --i) {
    int pos = b[i].second;
    s[pos].insert(b[i].first);
    used[pos] = true;
    if (pos > 0 and used[pos - 1]) merge_s(pos - 1, pos);
    if (pos + 1 < n and used[pos + 1]) merge_s(pos + 1, pos);
    while (nh.size()) {
      auto it = --nh.end();
      h.insert(*it);
      if (h.size() > q) h.erase(--h.end());
      if (h.size() == q) chmin(ans, (ll)(*h.rbegin() - *h.begin()));
      nh.erase(it);
    }
  }
  cout << ans << '\n';
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  solve();
  return 0;
}
