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

using ll = long long;
using VI = vector<int>;
using VVI = vector<vector<int>>;
using VVVI = vector<vector<vector<int>>>;
using VL = vector<ll>;
using VVL = vector<vector<ll>>;
using VVVL = vector<vector<vector<ll>>>;
using VD = vector<double>;
using VVD = vector<vector<double>>;
using VVVD = vector<vector<vector<double>>>;
using VB = vector<bool>;
using VVB = vector<vector<bool>>;
using P = pair<int, int>;
using VP = vector<P>;

#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define FOR(i, a, b) for (ll i = a; i < (ll)(b); i++)
#define ALL(a) (a).begin(),(a).end()

constexpr int INF = 1001001001;
constexpr ll LINF = 1001001001001001001ll;
constexpr int DX[] = {1, 0, -1, 0};
constexpr int DY[] = {0, 1, 0, -1};

template< typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true); }
template< typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true); }

const ll MOD = 1000000007;

int main() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int T;
    cin >> T;
    VI N(T);
    vector<string> S(T);
    REP(i, T) cin >> N[i] >> S[i];
    REP(i, T) {
        string ans = "";
        REP(j, N[i]) {
            ans.push_back(S[i][j]);
            int m = ans.size();
            while (m > 2 && ans.substr(m - 3, 3) == "ABB") {
                ans.pop_back();
                ans.pop_back();
                ans.pop_back();
                ans.push_back('B');
                m -= 2;
            }
            //cout << ans << " ";
        }
        cout << ans << endl;
    }
}