//============================================================================
// Name : ioi18p1.cpp
// Author : Daxi the Taxi
// Version :
// Copyright : ALL YOUR CODE IS BELONG TO US
// Description : Hello World in C++, Ansi-style
//============================================================================
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> p;
#ifndef ONLINE_JUDGE
int press(string s);
#endif
string guess_sequence(int n){
string cur = "",
ava[3];
// Guessing first letter
int ret = press("AB");
if(ret){
ret = press("A");
if(ret)
cur = "A", ava[0] = "B", ava[1] = "X", ava[2] = "Y";
else
cur = "B", ava[0] = "A", ava[1] = "X", ava[2] = "Y";
}
else{
ret = press("X");
if(ret)
cur = "X", ava[0] = "A", ava[1] = "B", ava[2] = "Y";
else
cur = "Y", ava[0] = "A", ava[1] = "B", ava[2] = "X";
}
// Rest of it
for (int i = 1; i < n - 1; ++i) {
ret = press(cur + ava[0] + ava[0] + cur + ava[1] + ava[0] + cur + ava[1] + ava[1]) - i;
if(ret == 1){
ret = press(cur + ava[0] + ava[2]) - i;
if(ret == 0) cur += ava[1] + ava[2];
else if(ret == 1) cur += ava[0] + ava[1];
else cur += ava[0] + ava[2];
i++;
}
else if(ret == 2){
ret = press(cur + ava[1] + ava[0]) - i;
if(ret == 0) cur += ava[0] + ava[0];
else if(ret == 1) cur += ava[1] + ava[1];
else cur += ava[1] + ava[0];
i++;
}
else cur += ava[2];
}
// Last letter if required
int sz = cur.size();
if(sz < n){
ret = press(cur + ava[0]);
if(ret > sz) cur += ava[0];
else{
ret = press(cur + ava[1]);
if(ret > sz) cur += ava[1];
else cur += ava[2];
}
}
return cur;
}
#ifdef WHEEEEEEE
const int N = 20;
const string STR = "ABYXXBYXYBBYXBYXXYBB";
int presscnt = 0;
int press(string s){
int sz = s.length(), ptr = 0, best = INT_MIN;
assert(sz <= N << 2);
for (int i = 0; i < sz; ++i) {
if(s[i] == STR[ptr])
ptr++;
else
ptr = 0;
best = max(best, ptr);
if(ptr == N) ptr = 0;
}
presscnt++;
return best;
}
int main(){
printf("%s\n", guess_sequence(N).c_str());
printf("presscnt=%d\n", presscnt);
return 0;
}
#endif
