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, s):
    q = []
    for i in range(n - 1, -1, -1):
        q.append(s[i])
        if len(q) >= 3:
            if q[-1] + q[-2] == 'AB' and q[-3] == 'B':
                q.pop()
                q.pop()
    return ''.join(q[::-1])


for _ in range(ii()):
    n = ii()
    s = input()
    print(solve(n, s))