import sys
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())

def solve():
    n = ii()
    s = list(input())

    while True:
        flag = True
        for i in range(len(s) - 2):
            if s[i] == 'A' and s[i + 1] == 'B' and s[i + 2] == 'B':
                s.pop(i)
                s.pop(i)
                flag = False
                break
        if flag:
            break
    print(''.join(s))

for _ in range(ii()):
    solve()