#include "combo.h"
#include <bits/stdc++.h>
#define IO_OP std::ios::sync_with_stdio(0); std::cin.tie(0);
#define F first
#define S second
#define V vector
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define SZ(v) int((v).size())
#define ALL(v) (v).begin(), (v).end()
using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef V<int> vi;
string _reset = "\u001b[0m", _yellow = "\u001b[33m", _bold = "\u001b[1m";
void DBG() { cerr << "]" << _reset << endl; }
template<class H, class...T> void DBG(H h, T ...t) {
cerr << to_string(h);
if(sizeof ...(t)) cerr << ", ";
DBG(t...);
}
#ifdef CHEISSMART
#define debug(...) cerr << _yellow << _bold << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define debug(...)
#endif
const int INF = 1e9 + 7;
string guess_sequence(int N) {
string s;
auto add_one = [&] () {
string t = s + "A" + s + "B";
if(press(t) > SZ(s)) {
if(press(s + "A") > SZ(s))
s += "A";
else
s += "B";
} else {
if(press(s + "X") > SZ(s))
s += "X";
else
s += "Y";
}
};
add_one();
string c;
for(char cc:"ABXY") if(cc != s[0]) c.PB(cc);
while(SZ(s) + 2 <= N) {
string t = s + c[0] + c[0] + s + c[0] + c[1] + s + c[0] + c[2] + s + c[1];
int tt = press(t);
if(tt == SZ(s))
s += c[2];
else if(tt == SZ(s) + 1)
s += c[1];
else
s += c[0];
}
add_one();
return s;
}
