import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int k = sc.nextInt();
        int[] scores = new int[n + 1];
        scores[0] = Integer.MIN_VALUE;
        scores[n] = Integer.MAX_VALUE / 2;
        for (int i = 1; i < n; i++) {
            scores[i] = sc.nextInt();
        }
        Arrays.sort(scores);
        int left = 0;
        int right = n;
        while (right - left > 1) {
            int x = (left + right) / 2;
            int idx = 1;
            int count = 0;
            for (int i = n - 1; i > idx; i--) {
                if (i == x) {
                    continue;
                }
                while (scores[i] + scores[idx] <= scores[x] + k || idx == x) {
                    idx++;
                }
                if (idx < i) {
                    count++;
                    idx++;
                }
            }
            if (count < m) {
                right = x;
            } else {
                left = x;
            }
        }
        if (right == n) {
            System.out.println(-1);
        } else {
            System.out.println(scores[right]);
        }
    }
}