#include "combo.h"
using namespace std;
#define ll long long
string guess_sequence(int n) {
string p, s = "";
string w = "ABXY";
if ( n == 1){
ll a = press("A"), b = press("B"), x = press("X");
if (a) return "A";
else if (b) return "B";
else if (x) return "X";
return "Y";
}
//find first letter (2 operations)
ll f = 0, x = press("AB");
if (x){
x = press("A");
if (x) f= 0;
else f = 1;
}
else{
x = press("X");
if (x) f = 2;
else f = 3;
}
s += w[f];
w.erase(w.begin() + f);
//dbg(w);
if (n == 1) return s;
//find all letters until n-1 (n-2 operations)
for (ll i =1; i<n-1; i++){
p = s + w[0] + s + w[1] + w[0] + s + w[1] + w[1] + s + w[1] + w[2];
//dbg2(s,p);
x = press(p);
if (x == i) s += w[2];
else if (x == i+1) s += w[0];
else s += w[1];
}
//find last letter (2 operations)
ll a = press(s + w[0]), b = press(s + w[1]);
if (a == b) s += w[2];
else if (a > b) s += w[0];
else s += w[1];
//dbg(s);
return s;
}
