import java.util.ArrayList; import java.util.Scanner; import java.util.TreeSet; public class Main { public static void main(String[] args) { ArrayList<Integer> list = new ArrayList<Integer>(); TreeSet<Integer> set = new TreeSet<Integer>(); Scanner scanner= new Scanner(System.in);                 String str = scanner.nextLine();                 int k = scanner.nextInt();                 String[] s = str.split(" ");          for(int i = 0; i < s.length; i++) { set.add(Integer.parseInt(s[i])); } if(k >= set.size() || k <= 0) { System.out.println(-1); } for(Integer i : set) { list.add(i); } System.out.println(list.get(list.size()-k)); } }