t = int(input())
for _ in range(t):
    n = int(input())
    S = input()
    ANS = ''
    for i in range(n - 1, -1, -1):
        ANS = S[i] + ANS
        if ANS[:2] == "AB":
            if len(ANS) > 2 and ANS[2] == 'B':
                ANS = ANS[2:]
    print(ANS)