import sys int1 = lambda x: int(x) - 1 # input = lambda: sys.stdin.buffer.readline() input = lambda: sys.stdin.readline().rstrip() ii = lambda: int(input()) i1 = lambda: int1(input()) mi = lambda: map(int, input().split()) mi1 = lambda: map(int1, input().split()) li = lambda: list(mi()) li1 = lambda: list(mi1()) lli = lambda n: [li() for _ in range(n)] INF = float("inf") mod = int(1e9 + 7) # mod = 998244353 for _ in range(ii()): n = ii() t = [] for c in input(): t.append(c) while len(t) >= 3 and t[-3:] == ["A", "B", "B"]: t.pop() t.pop() t.pop() t.append("B") print("".join(t))