#include "bits/stdc++.h"
#include "combo.h"
using namespace std;
#define ff first
#define ss second
#define all(v) v.begin(), v.end()
#define ll long long
#define pb push_back
#define pii pair<int, int>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define tr(i, c) for(auto i = c.begin(); i != c.end(); ++i)
#define wr puts("----------------")
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
string guess_sequence(int n){
string tm = "ABXY";
vector<char> use;
string ans = "";
if(press("AB")){
if(press("A")){
for(int i = 1; i <= 3; ++i)
use.pb(tm[i]);
ans += "A";
}
else{
use.pb('A');
for(int i = 2; i <= 3; ++i)
use.pb(tm[i]);
ans += "B";
}
}
else{
if(press("X")){
for(int i = 0; i <= 1; ++i)
use.pb(tm[i]);
use.pb('Y');
ans += "X";
}
else{
for(int i = 0; i <= 2; ++i)
use.pb(tm[i]);
ans += "Y";
}
}
assert((int)use.size() == 3);
if(n == 1)
return ans;
int x = 0;
for(int i = 0; i < n-2; ++i){
int s = (int)ans.size();
x = press(ans+use[0]+ans+use[1]+use[0]+ans+use[1]+use[1]+ans+use[1]+use[2]);
if(x == s+1)
ans += use[0];
else if(x == s+2)
ans += use[1];
else
ans += use[2];
}
if(press(ans+use[0]) == n)
ans += use[0];
else if(press(ans+use[1]) == n)
ans += use[1];
else
ans += use[2];
return ans;
}
