#include "combo.h"
#include<bits/stdc++.h>
using namespace std;
#define pb emplace_back
#define mp make_pair
#define ALL(x) x.begin(), x.end()
#define SZ(x) (int)x.size()
char ltrs[] = {'A', 'B', 'X', 'Y'};
vector<char> out;
string guess_sequence(int N) {
// cout<<N<<'\n';
int a = press("AB");
int b = press("AX");
if(a&&b)out.pb('A');
if (a&&!b)out.pb('B');
if (!a&&b)out.pb('X');
if(!a&&!b)out.pb('Y');
vector<char> V;
for (int i=0;i<4;++i)if(ltrs[i] != out[0])V.pb(ltrs[i]);
for (int x=2;x<N;++x){
string q = "";
for (auto i : out)q+=i;
q += V[0];
q += V[0];
for (auto i : out)q+=i;
q += V[0];
q += V[1];
for (auto i : out)q+=i;
q += V[0];
q += V[2];
for (auto i : out)q+=i;
q += V[1];
// cout<<q<<'\n';4
int res = press(q);
// cout<<res<<' '<<x<<'\n';
if (res == x-1){
out.pb(V[2]);
}else if (res == x+1){
out.pb(V[0]);
}else{
out.pb(V[1]);
}
assert(SZ(out)== x);
assert(x<N&&SZ(out)<N);
}
assert(SZ(out) > N-1);
string ret = "";
for (auto i : out)ret += i;
ret += V[0];
if (press(ret) == N)return ret;
ret = "";
for (auto i : out)ret += i;
ret += V[1];
if (press(ret) == N)return ret;
ret = "";
for (auto i : out)ret += i;
ret += V[2];
if (press(ret) == N)return ret;
assert(0);
}
