/* AM+DG */
/*
AB
A or X, depending on the last query's result
2 queries to get letter 1
Then N - 2 queries for everything except the last letter
Then 2 queries for the last letter
AZXAZYBAZYXAZYY
*/
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pi;
typedef pair<ll, ll> pll;
typedef vector<pi> vpi;
typedef vector<pll> vpll;
typedef vector<vpi> vvpi;
typedef vector<vpll> vvpll;
typedef vector<bool> vb;
#define IOS ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#define L(varll, mn, mx) for(ll varll = (mn); varll < (mx); varll++)
#define LR(varll, mx, mn) for(ll varll = (mx); varll > (mn); varll--)
#define LI(vari, mn, mx) for(int vari = (mn); vari < (mx); vari++)
#define LIR(vari, mx, mn) for(int vari = (mx); vari > (mn); vari--)
#define INPV(varvec) for(auto& varveci : (varvec)) cin >> varveci
#define fi first
#define se second
#define pb push_back
#define INF(type) numeric_limits<type>::max()
#define NINF(type) numeric_limits<type>::min()
#define TCASES int t; cin >> t; while(t--)
#include "combo.h"
// #define DEBUG
string guess_sequence(int N) {
string ans;
char first;
if(press("AB") > 0) {
if(press("A") > 0) first = 'A';
else first = 'B';
} else {
if(press("X") > 0) first = 'X';
else first = 'Y';
}
ans.pb(first);
if(N == 1) return ans;
string poss = "ABXY";
string nf;
LI(i, 0, 4) {
if(poss[i] == first) continue;
nf.pb(poss[i]);
}
LI(i, 0, N - 2) {
stringstream guess;
guess << ans;
guess << nf[1];
guess << ans;
guess << nf[2] << nf[0];
guess << ans;
guess << nf[2] << nf[1];
guess << ans;
guess << nf[2] << nf[2];
int guess_ans = press(guess.str());
ans.pb(nf[guess_ans - ((int)ans.size())]);
}
// Last letter
if(press(ans + "A" + ans + "B") == N) {
if(press(ans + "A") == N) ans.pb('A');
else ans.pb('B');
} else {
if(press(ans + "X") == N) ans.pb('X');
else ans.pb('Y');
}
return ans;
}
