//{
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double lf;
typedef pair<ll,ll> ii;
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define FILL(i,n) memset(i,n,sizeof i)
#define X first
#define Y second
#define SZ(_a) (int)_a.size()
#define ALL(_a) _a.begin(),_a.end()
#define pb push_back
#ifdef brian
#define debug(...) do{\
fprintf(stderr,"%s - %d (%s) = ",__PRETTY_FUNCTION__,__LINE__,#__VA_ARGS__);\
_do(__VA_ARGS__);\
}while(0)
template<typename T>void _do(T &&_x){cerr<<_x<<endl;}
template<typename T,typename ...S> void _do(T &&_x,S &&..._t){cerr<<_x<<" ,";_do(_t...);}
template<typename _a,typename _b> ostream& operator << (ostream &_s,const pair<_a,_b> &_p){return _s<<"("<<_p.X<<","<<_p.Y<<")";}
template<typename It> ostream& _OUTC(ostream &_s,It _ita,It _itb)
{
_s<<"{";
for(It _it=_ita;_it!=_itb;_it++)
{
_s<<(_it==_ita?"":",")<<*_it;
}
_s<<"}";
return _s;
}
template<typename _a> ostream &operator << (ostream &_s,vector<_a> &_c){return _OUTC(_s,ALL(_c));}
template<typename _a> ostream &operator << (ostream &_s,set<_a> &_c){return _OUTC(_s,ALL(_c));}
template<typename _a,typename _b> ostream &operator << (ostream &_s,map<_a,_b> &_c){return _OUTC(_s,ALL(_c));}
template<typename _t> void pary(_t _a,_t _b){_OUTC(cerr,_a,_b);cerr<<endl;}
#define IOS()
#else
#define debug(...)
#define pary(...)
#define endl '\n'
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0);
#endif // brian
//}
#include "combo.h"
std::string guess_sequence(int N) {
string s = "";
vector<char> v;
if(press("AB"))
{
if(press("A"))s.pb('A');
else s.pb('B');
}else{
if(press("X"))s.pb('X');
else s.pb('Y');
}
debug(s);
string m = "ABXY";
REP(i,4)if(s[0] != m[i])v.pb(m[i]);
while(SZ(s) < N-1)
{
string r = "";
r += s;
r.pb(v[0]);
r += s;
r.pb(v[1]);
r.pb(v[0]);
r += s;
r.pb(v[1]);
r.pb(v[1]);
r += s;
r.pb(v[1]);
r.pb(v[2]);
ll t = press(r);
if(t == SZ(s))s.pb(v[2]);
else if(t == SZ(s) + 1)s.pb(v[0]);
else s.pb(v[1]);
debug(s);
}
string r = s + "A" + s + "B";
debug(v);
if(press(r) == N)
{
if(press(s + "A") == N)s.pb('A');
else s.pb('B');
}
else
{
if(press(s + "X") == N)s.pb('X');
else s.pb('Y');
}
return s;
}
