There is a party at Shizuka's house. Everyone had gathered there. During the party, Dekisugi gave everyone a challenge.

He write a number consisting of N digits on a paper and asks everyone to form the largest possible number by deleting exactly K digits from that number. Also, after deletion digits of number can't be rearranged and the order of digits would remain same as in original number i.e. Suppose you have a number 3759 and you delete digits 3 and 5 from it, the number formed would be 79. Number can contain leading zeros.

Nobita wanted to prove his smartness in front of Shizuka but he is not smart enough to solve this problem and asks for your help.

Input

First line contains T - number of test cases.
Each test case contains two lines.

First line contains two integers N and K indicating number of digits in the original number and number of digits to be deleted respectively. Second line contains a N-digit number Dekisugi wrote on paper.

Output

A single line containing the largest number you can form from the given number after deleting exactly K digits from it.

Constraints

$1<= T <= 10$

$0<= K < N <=$10^4

Author: Karan Thakkar

Tester: Akshat Dua