#include "combo.h"
#include<bits/stdc++.h>
using namespace std;
typedef int ll;
typedef pair<ll,ll> pl;
typedef vector<ll> vl;
#define po pop_back
#define pb push_back
#define mk make_pair
#define lw lower_bound
#define up upper_bound
#define ff first
#define ss second
#define boost ios_base::sync_with_stdio(); cin.tie(0); cout.tie(0);
#define MOD 1000000007
#define MAX 1e18
#define MIN -1e18
#define rep(i,a,b) for(ll i=a;i<=b;i++)
#define per(i,a,b) for(ll i=b;i>=a;i--)
#define con continue
#define freopen freopen("input.txt", "r", stdin);freopen("output.txt", "w", stdout);
#define PI 3.14159265358979323846264338327950288419716939937510582097494459230781640628
// typedef tree<ll , null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
// template< typename T>
// using indexed_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
ll n,m,ans,mid,mn,mx,T,sum,h1,h2,e[1234567],b[1234567],c[1234567],d[1<<20],k,i,j,l,r,h,a[1234567],w,x,y,z,res,cnt,sz;
bool used[1234567];
vector<ll> v[1234567],vec,vv1,vv2;
string s1,s;
ll dx[4]={-1,1,0,0},dy[4]={0,0,-1,1};
string guess_sequence(int n) {
vector<string> vec{"A","B","C","D"};
int x = -1;
if(press("AB")) {
if(press("A")) x = 0;
else x = 1;
} else if(press("X")) x = 2;
else x = 3;
string ans = vec[x];
vec.erase(vec.begin() + x);
for(int i = 1; i < n - 1; i++) {
string s = ans+vec[0]+vec[0]+ans+vec[0]+vec[1]+ans+vec[0]+vec[2]+ans+vec[1];
int x = press(s);
if(x == i + 2) ans += vec[0];
else if(x == i+1) ans += vec[1];
else ans += vec[2];
}
if(n > 1){
if(press(ans+vec[0]) == n) ans += vec[0];
else if(press(ans + vec[1]) == n) ans += vec[1] ;
else ans += vec[2];
}
return ans;
}
