from collections import deque

def solve(n, s):
    q = deque()
    for i in range(n - 1, -1, -1):
        q.appendleft(s[i])
        if len(q) >= 3:
            if q[0] + q[1] == 'AB' and q[2] == 'B':
                q.popleft()
                q.popleft()
    return ''.join(q)


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