#include<bits/stdc++.h>
/*namespace {
constexpr int MAX_N = 2000;
constexpr int MAX_NUM_MOVES = 8000;
int N=100;
std::string S="ABXYXBBYYX";
int num_moves;
void wrong_answer(const char *MSG) {
printf("Wrong Answer: %s\n", MSG);
exit(0);
}
} //namespace
int press(std::string p) {
if (++num_moves > MAX_NUM_MOVES) {
wrong_answer("too many movesq");
}
int len = p.length();
if (len > 4 * N) {
wrong_answer("invalid pressqq");
}
for (int i = 0; i < len; ++i) {
if (p[i] != 'A' && p[i] != 'B' && p[i] != 'X' && p[i] != 'Y') {
wrong_answer("invalid pressqqq");
}
}
int coins = 0;
for (int i = 0, j = 0; i < len; ++i) {
if (j < N && S[j] == p[i]) {
++j;
} else if (S[0] == p[i]) {
j = 1;
} else {
j = 0;
}
coins = std::max(coins, j);
}
return coins;
}*/
int press(std::string p);
std::string guess_sequence(int N){
std::string ans="";
char s[4];
if(press("A")==1)ans="A",s[0]='A',s[1]='B',s[2]='X',s[3]='Y';
else if(press("B")==1)ans="B",s[0]='B',s[1]='A',s[2]='X',s[3]='Y';
else if(press("X")==1)ans="X",s[0]='X',s[1]='B',s[2]='A',s[3]='Y';
else ans="Y",s[0]='Y',s[1]='B',s[2]='X',s[3]='A';
for(int i=2;i<=N-1;i++){
std::string now1 = ans;now1+=s[1];
std::string now2 = ans;now2+=s[2];now2+=s[1];
std::string now3 = ans;now3+=s[2];now3+=s[2];
std::string now4 = ans;now4+=s[2];now4+=s[3];
std::string tt = now1+now2+now3+now4;
int x = press(tt);
if(x==i-1)ans = ans+s[3];
else if(x==i)ans = ans+s[1];
else ans = ans+s[2];
}if(press(ans+s[1])==N){
ans+=s[1];return ans;
}
if(press(ans+s[1])==N){
ans+=s[2];return ans;
}
else{
ans+=s[3];return ans;
}
}
/*int main(){
std::cout<<(guess_sequence(10)==S);
}*/
