import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;
import java.math.*;

public class Main {
    static int[][] dp;
    static TreeMap<Integer, Integer> values = new TreeMap<>();
    static int[] arr;
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner();
        int n = sc.nextInt();
        values.put(sc.nextInt(), n + 1);
        arr = new int[n + 2];
        arr[n + 1] = values.lastKey();
        int k = sc.nextInt();
        for (int i = 1; i <= n; i++) {
            int x = sc.nextInt();
            values.put(x, i);
            arr[i] = x;
        }
        values.put(0, 0);
        dp = new int[2][n + 2];
        int left = 0;
        int right = values.lastKey();
        while (right - left > 1) {
            int m = (left + right) / 2;
            for (int[] arr : dp) {
                Arrays.fill(arr, -1);
            }
            if (dfw(n + 1, 1, m) <= n - k) {
                left = m;
            } else {
                right = m;
            }
        }
        System.out.println(left);
    }
    
    static int dfw(int idx, int v, int w) {
        if (v < 0) {
            return 0;
        }
        if (idx <= 0 || arr[idx] < w) {
            return Integer.MAX_VALUE / 2;
        }
        if (dp[v][idx] < 0) {
            int target = values.floorEntry(arr[idx] - w).getValue();
            dp[v][idx] = Math.min(dfw(idx - 1, v, w), dfw(target, v - 1, w) + idx - target - 1);
        }
        return dp[v][idx];
    }
} 

class FastScanner {
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;
    private static final int BUFFER_SIZE = 1 << 16; // 65,536 バイト

    public FastScanner() {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    private byte read() {
        try {
            if (bufferPointer == bytesRead) {
                bytesRead = din.read(buffer, 0, BUFFER_SIZE);
                if (bytesRead == -1) return -1;
                bufferPointer = 0;
            }
            return buffer[bufferPointer++];
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String next() {
        byte b = read();
        // 空白文字を読み飛ばす
        while (isSpaceChar(b)) {
            b = read();
        }
        StringBuilder sb = new StringBuilder();
        while (!isSpaceChar(b)) {
            sb.append((char) b);
            b = read();
        }
        return sb.toString();
    }

    public int nextInt() {
        int ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public long nextLong() {
        long ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10L + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public double nextDouble() {
        double ret = 0, div = 1;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c) && c != '.');
        if (c == '.') {
            while (!isSpaceChar(c = read())) {
                ret += (c - '0') / (div *= 10);
            }
        }
        return neg ? -ret : ret;
    }

    private boolean isSpaceChar(byte c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public void close() {
        try {
            if (din != null) din.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}