#include <bits/stdc++.h>
//#include "grader.cpp"
//#include "grader.h"
#include "combo.h"
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//#define in(x) freopen(x, "r", stdin)
//#define out(x) freopen(x, "w", stdout)
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("-O3")
//#define F first
//#define S second
//#define pb push_back
//#define N +100500
//#define M ll(1e9 + 7)
#define sz(x) (int)x.size()
//#define re return
//#define oo ll(1e18)
//#define el '\n'
using namespace std;
//using namespace __gnu_pbds;
//typedef tree <int, null_type, less_equal <int> , rb_tree_tag, tree_order_statistics_node_update> ordered_set;
//typedef long long ll;
//typedef long double ld;
void swap(char &x, char &y)
{
char t = x;
x = y;
y = t;
}
string guess_sequence(int n)
{
string s = "";
char c[4];
c[0] = 'A';
c[1] = 'B';
c[2] = 'X';
c[3] = 'Y';
s += c[0];
s += c[1];
int p = press(s);
if (p > 0)
{
s = "";
s += c[0];
p = press(s);
if (p > 0) swap(c[0], c[3]);
else
{
s = "";
s += c[1];
swap(c[1], c[3]);
}
}
else
{
s = "";
s += c[2];
p = press(s);
if (p > 0) swap(c[2], c[3]);
else
{
s = "";
s += c[3];
}
}
for (int len = 2; len < n; len++)
{
string maybeone = s + c[0] + c[0] + s + c[0] + c[1] + s + c[0] + c[2] + s + c[2];
p = press(maybeone);
if (p == len + 1) s += c[0];
else if (p == len) s += c[2];
else s += c[1];
}
p = press(s + c[0]);
if (p == n) return s + c[0];
p = press(s + c[1]);
if (p == n) return s;
return s + c[2];
}
//int main()
//{
// srand(time(0));
// ios_base::sync_with_stdio(0);
// iostream::sync_with_stdio(0);
// ios::sync_with_stdio(0);
// cin.tie(NULL);
// cout.tie(NULL);
//
//// in("input.txt");
//// out("output.txt");
//
// ABXXBYXBB
//}
