//g++ 1.cpp -std=c++14 -O2 -I .
#include <bits/stdc++.h>
using namespace std;

#include <atcoder/math>
#include <atcoder/modint>
using namespace atcoder;

using ll = long long;
using ld = long double;

using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vld = vector<ld>;
using vvld = vector<vld>;
using vst = vector<string>;
using vvst = vector<vst>;

#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define pq_big(T) priority_queue<T,vector<T>,less<T>>
#define pq_small(T) priority_queue<T,vector<T>,greater<T>>
#define all(a) a.begin(),a.end()
#define rep(i,start,end) for(ll i=start;i<(ll)(end);i++)
#define per(i,start,end) for(ll i=start;i>=(ll)(end);i--)
#define uniq(a) sort(all(a));a.erase(unique(all(a)),a.end())

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

  reverse(all(s));

  stack<char> st;
  for(char c:s){
    if(st.size()==0||c=='B'){
      st.push(c);
      continue;
    }
    if(st.top()=='B'){
      if(st.size()==1){
        st.push(c);
        continue;
      }
      st.pop();
      if(st.top()=='A'){
        st.push('B');
        st.push(c);
        continue;
      }
    }
  }

  while(st.size()!=0){
    cout<<st.top();
    st.pop();
  }
  cout<<endl;
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int t;
  cin>>t;
  
  while(t--){
    solve();
  }
}

/*

AB hoge...
hoge...

hogeの頭2文字
A,AA 消さない
B,BA,BB 消す
ABの時

ABAB hoge...
AB hoge...


*/