#include "combo.h"
#include <iostream>
#include <algorithm>
#include <queue>
#include <cmath>
#include <vector>
#include <list>
#include <string>
#include <unordered_map>
#include <map>
#include <set>
#include <stack>
#include <string>
#include <iomanip>
#include <fstream>
using namespace std;
void fastio() {
ios_base::sync_with_stdio(false);
cin.tie(0);
}
const long long mod = 1e9+7;
const int N = 3e6+5;
int a[N] , dp[N];
string guess_sequence(int N){
string s;
if(press("A")){
s = "A";
}
if(press("B")){
s = "B";
}
if(press("X")){
s = "X";
}
if(press("Y")){
s = "Y";
}
if(N == 1){
return s;
}
string chars;
for (char c : "ABXY") {
if (c != s[0]) chars += c;
}
for (int i = 0; i < N - 2; i++) {
int x = press(
s + chars[0] + chars[0] +
s + chars[0] + chars[1] +
s + chars[0] + chars[2] +
s + chars[1]);
if (x == (int)s.size()) {
s += chars[2];
} else if (x == (int)s.size() + 1) {
s += chars[1];
} else {
s += chars[0];
}
}
int x = press(s + chars[0] + s + chars[1]);
if (x == N) {
x = press(s + chars[0]);
if (x == N) {
return s + chars[0];
} else {
return s + chars[1];
}
} else {
return s + chars[2];
}
}
// int main() {
// return 0;
// }
