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

int main()
{
    int T;
    cin >> T;
    while (T--)
    {
        int N;
        cin >> N;
        string s;
        cin >> s;
        string a;
        for (char c : s)
        {
            a += c;
            while (a.size() >= 3 && a.substr(a.size() - 3, 3) == "ABB")
            {
                a.pop_back();
                a.pop_back();
                a.pop_back();
                a.push_back('B');
            }
        }
        cout << a << endl;
    }
}