#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
using ll = long long;
#define all(v) v.begin(), v.end()
string guess_sequence(int N){
string a[4] = {"A", "B", "X", "Y"};
string res = "";
int ix;
int l = press("AB");
if(l != 0){
l = press("A");
if(l == 1){
res = "A";
ix = 0;
}else{
res = "B";
ix = 1;
}
}else{
l = press("X");
if(l == 1){
res = "X";
ix = 2;
}else{
res = "Y";
ix = 3;
}
}
if(N == 1) return res;
while(res.size() < N - 1){
string tmp = "";
tmp += res + a[(ix + 1) % 4] + a[(ix + 1) % 4];
tmp += res + a[(ix + 1) % 4] + a[(ix + 2) % 4];
tmp += res + a[(ix + 1) % 4] + a[(ix + 3) % 4];
tmp += res + a[(ix + 2) % 4];
int x = press(tmp);
if(x == res.size()) res += a[(ix + 3) % 4];
else if(x == res.size() + 1) res += a[(ix + 2) % 4];
else res += a[(ix + 1) % 4];
}
int cnt = 0;
for(int i = 0; i < 4; i++){
if(ix == i) continue;
if(cnt == 2) break;
if(press(res + a[i]) == N){
return res + a[i];
}
cnt++;
}
if(ix == 3) return res + a[2];
else return res + a[3];
}
