Given a string consisting of lowercase letters, arrange all its letters in ascending order.
The first line of the input contains T, denoting number of testcases. Then follows description of each testcase. The first line of the testcase contains positive integer N denoting the length of string. The second line contains the string.
For each testcase, output the sorted string.
1 <= T <= 100
1 <= N <= 100
Testcase 1: The given string in sorted order of its letters is: abcde