//  ↘ ⬇ ⬇ ⬇ ⬇ ⬇ ↙
//  ➡ @roadfromroi ⬅
//  ↗ ⬆ ⬆ ⬆ ⬆ ⬆ ↖
#include <iostream>
#include "vector"
#include "algorithm"
#include "numeric"
#include "climits"
#include "iomanip"
#include "bitset"
#include "cmath"
#include "map"
#include "deque"
#include "array"
#include "set"
#include "combo.h"
#define all(x) x.begin(), x.end()
using namespace std;
char getc(char c, char crb) {
    if (c >= crb)
        return c + 1;
    return c;
}
string tepa = "ABXY";
int prs(string s) {
    for (auto &i : s)
        i = tepa[i-'A'];
    //cout << s << endl;
    return press(s);
}
string mv(string s) {
    for (auto &i : s)
        i = tepa[i-'A'];
    return s;
}
string guess_sequence(int n) {
    string ba = "BA";
    int coins = prs(ba);
    char cba;
    if (coins > 0) {
        string reba = "A";
        coins = prs(reba);
        if (coins) {
            cba = 'A';
        } else {
            cba = 'B';
        }
    } else {
        string reba = "C";
        coins = prs(reba);
        if (coins) {
            cba = 'C';
        } else {
            cba = 'D';
        }
    }
    if (n == 1) {
        string s(1, cba);
        return mv(s);
    }
    string corba(1, cba);
    for (int i = 1; i < n - 1; ++i) {
        string res;
        res += corba + getc('A', cba);
        for (int j = 0; j < 3; ++j) {
            res += corba + getc('B', cba) + getc('A' + j, cba);
        }
        coins = prs(res);
        if (coins == corba.size())
            corba += getc('C', cba);
        else if (coins == corba.size() + 1)
            corba += getc('A', cba);
        else if (coins == corba.size() + 2)
            corba += getc('B', cba);
        else
            while (1);
    }
    string res = corba + getc('A', cba);
    if (prs(res) == n)
        return mv(res);
    res = corba + getc('B', cba);
    if (prs(res) == n) {
        return mv(res);
    }
    res = corba + getc('C', cba);
    //cerr << res << endl;
    return mv(res);
}
/*
namespace {

    constexpr int MAX_N = 2000;
    constexpr int MAX_NUM_MOVES = 8000;

    int N;
    std::string S;

    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 moves");
    }
    int len = p.length();
    if (len > 4 * N) {
        wrong_answer("invalid press");
    }
    for (int i = 0; i < len; ++i) {
        if (p[i] != 'A' && p[i] != 'B' && p[i] != 'X' && p[i] != 'Y') {
            wrong_answer("invalid press");
        }
    }
    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 main() {
    S = string(2000, 'Y');
    S[0] = 'X';
    N = S.length();
    num_moves = 0;
    std::string answer = guess_sequence(N);
    if (answer != S) {
        wrong_answer("wrong guess");
        exit(0);
    }
    printf("Accepted: %d\n", num_moves);
    return 0;
}
*/