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Time Limit: 1.0 s

Memory Limit: 256.0 MB

You are given a string S containing n characters. You need to find out the lexicographically smallest string after performing at most m operations (possibly zero).

In each operation, you can select two indices i and j (\(1 \le i,j \le n\)), and swap their characters. For example, for S = "abaa", if you select indices 1 and 2, then swap(S[1], S[2]). After the swap, the string becomes S="baaa".

Input

First line contains a positive integers T, which denotes number of test cases.

In each test case, the first line contains n and m, the length of the string and the number of operations, respectively.

The second line contains the string S of length n.

\(1 \le T \le 10^4\)
\(1 \le n \le 10^5\)
\(1 \le m \le 10^9\)

Note: String S contains english lowercase alphabet only. It is guranteed that sum of n over all test cases doesn't exceed \(2 \times 10^5\).

Output

For each test case, print the lexicographically smallest string S after performing at most m operations.

Sample

2
4 2
bbaa
5 1
abbac

aabb
aabbc