#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<vector>
#include<queue>
#include<bitset>
#include<string>
#include<stack>
#include<set>
#include<unordered_set>
#include<map>
#include<unordered_map>
#include<cstring>
#include<complex>
#include<cmath>
#include<iomanip>
#include<numeric>
#include<algorithm>
#include<list>
#include<functional>
#include<cassert>
#define mp make_pair
#define pb push_back
#define X first
#define Y second
#define y0 y12
#define y1 y22
#define INF 1987654321987654321
#define PI 3.141592653589793238462643383279502884
#define fup(i,a,b,c) for(int (i)=(a);(i)<=(b);(i)+=(c))
#define fdn(i,a,b,c) for(int (i)=(a);(i)>=(b);(i)-=(c))
#define MEM0(a) memset((a),0,sizeof(a));
#define MEM_1(a) memset((a),-1,sizeof(a));
#define ALL(a) a.begin(),a.end()
#define SYNC ios_base::sync_with_stdio(false);cin.tie(0)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> Pi;
typedef pair<ll, ll> Pll;
typedef pair<ld, ld> Pd;
typedef vector<int> Vi;
typedef vector<ll> Vll;
typedef vector<double> Vd;
typedef vector<Pi> VPi;
typedef vector<Pll> VPll;
typedef vector<Pd> VPd;
typedef tuple<int, int, int> iii;
typedef tuple<int,int,int,int> iiii;
typedef tuple<ll, ll, ll> LLL;
typedef vector<iii> Viii;
typedef vector<LLL> VLLL;
typedef complex<double> base;
const ll MOD = 1000000007;
ll POW(ll a, ll b, ll MMM = MOD) {ll ret=1; for(;b;b>>=1,a=(a*a)%MMM)if(b&1)ret=(ret*a)% MMM; return ret; }
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { if (a == 0 || b == 0)return a + b; return a*(b / gcd(a, b)); }
int dx[] = { 0,1,0,-1,1,1,-1,-1 }, dy[] = { 1,0,-1,0,1,-1,1,-1 };
#include "combo.h"
string guess_sequence(int N)
{
string ans;
vector<char> s;
if(press("AB")!=0)
{
s.pb('X');
s.pb('Y');
if(press("A")!=0)
{
ans+='A';
s.pb('B');
}
else
{
ans+='B';
s.pb('A');
}
}
else
{
s.pb('A');
s.pb('B');
if(press("X")!=0)
{
ans+='X';
s.pb('Y');
}
else
{
ans+='Y';
s.pb('X');
}
}
fup(i,2,N-1,1)
{
int t=press(ans+s[0]+s[0]+ans+s[0]+s[1]+ans+s[0]+s[2]+ans+s[1]);
if(t==i+1)ans+=s[0];
else if(t==i)ans+=s[1];
else ans+=s[2];
}
if(press(ans+s[0]+ans+s[1])==N)
{
if(press(ans+s[0])==N)ans+=s[0];
else ans+=s[1];
}
else ans+=s[2];
return ans;
}
