Find the kth Smallest Distinct Number

You are given (n) positive integers. Your task is to find the (k)-th smallest distinct integer among them. That is, first remove duplicates from the list, sort the remaining integers in non-decreasing order, and then output the (k)-th element (1-indexed). If there are fewer than (k) distinct integers, output (-1).

Formally, given a list (A = [a_1, a_2, \dots, a_n]), let (D = {a_i : 1 \leq i \leq n}) be the set of unique integers. Sort (D) in ascending order and find the element at index (k) (1-indexed).

inputFormat

The first line of the input contains two space-separated integers (n) and (k).

The second line contains (n) space-separated positive integers (a_1, a_2, \dots, a_n).

outputFormat

Output a single integer, which is the (k)-th smallest distinct number. If (k) is greater than the number of distinct integers, output (-1).

sample

6 3
1 2 3 4 5 6

3