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

int main(){
    int64_t T; cin >> T;
    while(T--){
        int64_t N; cin >> N;
        string S; cin >> S;
        string res = "";
        for(auto c : S){
            res.push_back(c);
            while(true){
                int64_t sz = res.size();
                if(res.size() < 3) break;
                if(res[sz-3] == 'A' and res[sz-2] == 'B' and res[sz-1] == 'B'){
                    res.pop_back();
                    res.pop_back();
                    res.pop_back();
                    res.push_back('B');
                }else{
                    break;
                }
            }
        }
        cout << res << '\n';
    }
}