#include <bits/stdc++.h>


#include <algorithm>
#include <cassert>
#include <vector>

namespace rklib {

template <class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
bool chmin_non_negative(T &a, const T &b) {
    if (a < 0 || a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
T div_floor(T a, T b) {
    if (b < 0) a *= -1, b *= -1;
    return a >= 0 ? a / b : (a + 1) / b - 1;
}

template <class T>
T div_ceil(T a, T b) {
    if (b < 0) a *= -1, b *= -1;
    return a > 0 ? (a - 1) / b + 1 : a / b;
}

}  // namespace rklib


#define For(i, a, b) for (int i = (int)(a); (i) < (int)(b); ++(i))
#define rFor(i, a, b) for (int i = (int)(a)-1; (i) >= (int)(b); --(i))
#define rep(i, n) For(i, 0, n)
#define rrep(i, n) rFor(i, n, 0)
#define fi first
#define se second

using namespace std;
using namespace rklib;

using lint = long long;
using pii = pair<int, int>;
using pll = pair<lint, lint>;

void solve() {
    int n;
    string s;
    cin >> n >> s;

    deque<char> dq;
    rrep(i, n) {
        if (s[i] == 'A' && !dq.empty() && dq[0] == 'B') {
            if (dq.size() >= 2 && dq[1] == 'B') {
                dq.pop_front();
            } else {
                dq.push_front(s[i]);
            }
        } else {
            dq.push_front(s[i]);
        }
    }

    for (auto c : dq) printf("%c", c);
    puts("");
}

int main() {
    int t;
    cin >> t;
    rep(tt, t) solve();
}