#include <iostream>
#include <vector>
#include <algorithm>
#include <atcoder/modint>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)

using m32 = atcoder::modint998244353;

int main(){
    int T; cin >> T;
    while(T --> 0){
        int N; cin >> N;
        string S; cin >> S;
        string buf;
        for(char c : S){
            if(c == 'B'){
                while(buf.size() >= 2 && buf.substr(buf.size() - 2) == "AB"){
                    rep(t,2) buf.pop_back();
                }
            }
            buf.push_back(c);
        }
        cout << buf << '\n';
    }
    return 0;
}

struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;