import sys
#input = sys.stdin.readline
#input = sys.stdin.buffer.readline #文字列はダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
#MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]
#dx8 = [1,1,0,-1,-1,-1,0,1]
#dy8 = [0,1,1,1,0,-1,-1,-1]
#dx = [1,1,-1,-1]
#dy = [1,-1,1,-1]

def main():
    T = int(input())
    for _ in range(T):
        N = int(input())
        left = deque(input())
        right = deque([])
        while left:
            #print(left,right)
            if not right:
                s = left.pop()
                right.appendleft(s)
            else:
                if left[-1] == "A" and right[0] == "B":
                    if len(left) <= 1 and len(right) <= 1:
                        s = left.pop()
                        right.appendleft(s)
                    elif len(left) <= 1:
                        if right[1] == "B":
                            #消す
                            left.pop()
                            right.popleft()
                        else:
                            s = left.pop()
                            right.appendleft(s)
                    elif len(right) <= 1:
                        s = left.pop()
                        right.appendleft(s)       
                    else:
                        if right[1] == "B":
                            #消す
                            left.pop()
                            right.popleft()
                        else:
                            s = left.pop()
                            right.appendleft(s)
                else:
                    s = left.pop()
                    right.appendleft(s)
        print("".join(right))                 



if __name__ == '__main__':
    main()