using System;
using System.IO;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;

partial class Solver {

    public void Run() {
        var n = ni();
        var k = ni();
        var q = ni();
        var A = ni(n);

        var B = A.Select((x, i) => new { Value = x, Index = i })
            .GroupBy(g => g.Value)
            .OrderBy(g => g.Key)
            .ToArray();

        var removed = new bool[n + 1];
        removed[n] = true;
        long ans = long.MaxValue;

        foreach (var g in B) {
            var list = new List<int>();
            var all = new List<int>();
            for (int i = 0; i <= n; i++) {
                if (removed[i]) {
                    if (list.Count >= k) {
                        list.Sort();
                    }
                    for (int j = 0; j < list.Count - (k - 1); j++) {
                        all.Add(list[j]);
                    }
                    list.Clear();
                } else {
                    list.Add(A[i]);
                }
            }

            all.Sort();
            if (all.Count >= q) {
                ans = Math.Min(ans, all[q - 1] - all[0]);
            } else {
                break;
            }

            foreach (var b in g) {
                removed[b.Index] = true;
            }
        }

        cout.WriteLine(ans);
    }
}

// PREWRITEN CODE BEGINS FROM HERE
partial class Solver : Scanner {
    public static void Main(string[] args) {
        new Solver(Console.In, Console.Out).Run();
    }

    private readonly TextReader cin;
    private readonly TextWriter cout;

    public Solver(TextReader reader, TextWriter writer)
        : base(reader) {
        this.cin = reader;
        this.cout = writer;
    }
    public Solver(string input, TextWriter writer)
        : this(new StringReader(input), writer) {
    }

    private int ni() { return NextInt(); }
    private int[] ni(int n) { return NextIntArray(n); }
    private long nl() { return NextLong(); }
    private long[] nl(int n) { return NextLongArray(n); }
    private double nd() { return NextDouble(); }
    private string ns() { return Next(); }
    private string[] ns(int n) { return NextArray(n); }
}

public class Scanner {
    private TextReader Reader;
    private Queue<string> TokenQueue = new Queue<string>();
    private readonly CultureInfo ci = CultureInfo.InvariantCulture;

    public Scanner()
        : this(Console.In) {
    }

    public Scanner(TextReader reader) {
        this.Reader = reader;
    }

    public int NextInt() { return int.Parse(Next(), ci); }
    public long NextLong() { return long.Parse(Next(), ci); }
    public double NextDouble() { return double.Parse(Next(), ci); }
    public string[] NextArray(int size) {
        var array = new string[size];
        for (int i = 0; i < size; i++) array[i] = Next();
        return array;
    }
    public int[] NextIntArray(int size) {
        var array = new int[size];
        for (int i = 0; i < size; i++) array[i] = NextInt();
        return array;
    }

    public long[] NextLongArray(int size) {
        var array = new long[size];
        for (int i = 0; i < size; i++) array[i] = NextLong();
        return array;
    }

    public string Next() {
        if (TokenQueue.Count == 0) {
            if (!StockTokens()) throw new InvalidOperationException();
        }
        return TokenQueue.Dequeue();
    }

    public bool HasNext() {
        if (TokenQueue.Count > 0)
            return true;
        return StockTokens();
    }

    private bool StockTokens() {
        while (true) {
            var line = Reader.ReadLine();
            if (line == null) return false;
            var tokens = line.Trim().Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
            if (tokens.Length == 0) continue;
            foreach (var token in tokens)
                TokenQueue.Enqueue(token);
            return true;
        }
    }
}


Measured memory_bytes: 33364