#include <bits/stdc++.h>
using namespace std;

int main()
{
	int T;
	cin >> T;
	int N;
	string S;
	deque<char> dq;
	int ds;
	for(int t = 0; t < T; t++)
	{
		cin >> N >> S;
		for(int i = 0; i < N; i++)
		{
			dq.push_back(S[i]);
			while((int)dq.size() >= 3)
			{
				ds = (int)dq.size();
				if(dq[ds - 3] == 'A' && dq[ds - 2] == 'B' && dq[ds - 1] == 'B')
				{
					dq.pop_back();
					dq.pop_back();
					dq.pop_back();
					dq.push_back('B');
				}
				else break;
			}
		}
		while(!dq.empty())
		{
			cout << dq.front();
			dq.pop_front();
		}
		cout << endl;
	}
	return 0;
}