C. Less or Equaltime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou are given a sequence of integers of length n and integer number k. You should print any integer number x in the range of [1; 10^9] (i.e. 1 \le x \le 10^9) such that exactly k elements of given sequence are less than or equal to x.Note that the sequence can contain equal elements.If there is no such x, print "-1" (without quotes).InputThe first line of the input contains integer numbers n and k (1 \le n \le 2 \cdot 10^5, 0 \le k \le n). The second line of the input contains n integer numbers a_1, a_2, \dots, a_n (1 \le a_i \le 10^9) — the sequence itself.OutputPrint any integer number x from range [1; 10^9] such that exactly k elements of given sequence is less or equal to x.If there is no such x, print "-1" (without quotes).ExamplesInput7 43 7 5 1 10 3 20Output6Input7 23 7 5 1 10 3 20Output-1NoteIn the first example 5 is also a valid answer because the elements with indices [1, 3, 4, 6] is less than or equal to 5 and obviously less than or equal to 6.In the second example you cannot choose any number that only 2 elements of the given sequence will be less than or equal to this number because 3 elements of the given sequence will be also less than or equal to this number.
Input7 43 7 5 1 10 3 20
Output6
['sortings', '*1200']