#include <bits/stdc++.h>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <string>
#include "combo.h"
using namespace std;
typedef long long ll;
string guess_sequence(int N) {
string S, p;
S = "";
char F;
if(press("AB")){
if(press("B")){S += "B"; F = 'B';}
else{S += "A"; F = 'A';}
} else {
if(press("X")){S += "X"; F = 'X';}
else{S += "Y"; F = 'Y';}
}
if(N==1){return S;}
string c = "";
if(F != 'A'){
c += 'A';
}
if(F != 'B'){
c += 'B';
}
if(F != 'X'){
c += 'X';
}
if(F != 'Y'){
c += 'Y';
}
for(ll i=0;i<N-2;i++){
p = S + c[0] + S + c[1] + c[0] + S + c[1] + c[1] + S + c[1] + c[2];
//cout<<p<<endl;
//cout<<"meow"<<endl;
ll k = press(p);
if(k == S.size()){
S += c[2];
}
if(k == S.size() + 1){
S += c[0];
}
if(k == S.size() + 2){
S += c[1];
}
}
p = S + c[0] + S + c[1];
ll k = press(p);
if(k == N){
if(press(S + c[0]) == N){S += c[0];}
else{S += c[1];}
} else {
S += c[2];
}
//cout<<S<<endl;
return S;
}
