#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(ll i=a;i<b;i++)
#define rrep(i,a,b) for(ll i=a-1;i>=b;i--)
#define ll long long
#define ull unsigned ll
#define ld long double
#define bl __int128_t
#define fi first
#define se second
#define vel vector<ll>
#define vvel vector<vel>
#define pll pair<ll,ll>
#define vepll vector<pll>
#define vvepll vector<vepll>
#define ves vector<string>
#define vem vector<mint>
#define vvem vector<vem>
#define pmm pair<mint,mint>
#define cleout(i) cout<<fixed<<setprecision(i)
template<class T>using PQ=priority_queue<T,vector<T>,greater<T>>;
//               上  右 下 左
vector<int> di={-1, 0, 1, 0};
vector<int> dj={ 0, 1, 0,-1};

vector<int> dx={ 0, 1, 0,-1};
vector<int> dy={ 1, 0,-1, 0};


vector<int> ddx={ 1, 1, 1, 0, -1, -1, -1, 0 };
vector<int> ddy={ 1, 0, -1, -1, -1, 0, 1, 1 };

ll inf=1000000000000000000;//1e18
// LLONG_MAX

mt19937_64 rng((ull)chrono::steady_clock::now().time_since_epoch().count());

//[x^M]1/(1-x)^N=comb(N-1+M,M)



vector<int> EulerianTrail(const int s, vvel &g, const bool directed) {
        function<void (int, vector<int> &)> dfs = [&](int u, vector<int> &trail) {
                while (!g[u].empty()) {
                        int v = g[u].back();
                        g[u].pop_back();
                        if (!directed) {
                                for (int i = 0; i < g[v].size(); i ++) {
                                        if (g[v][i] == u) {
                                                g[v].erase(g[v].begin() + i);
                                                break;
                                        }
                                }
                        }
                        dfs(v, trail);
                }
                trail.push_back(u);
        };
        vector<int> trail;
        dfs(s, trail);
        reverse(trail.begin(), trail.end());
        return trail;
}
//https://kokiymgch.hatenablog.com/entry/2017/12/07/193238#g

void _solve(){
    vvel G(26);
    rep(i,0,26){
        rep(j,0,26)G[i].push_back(j);
    }
    vector<int> ans=EulerianTrail(0,G,1);
    rep(i,1,ans.size()){
        char c=('A'+ans[i-1]);
        char d=('A'+ans[i]);
        cout<<c<<d<<"\n";
    }
}


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

    
    ll _;
    bool multitest=1;
    if(multitest)cin>>_;
    else _=1;
    rep(__,0,_){
        _solve();
    }
}