#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
typedef long long ll;
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
int query(string str);
int N;
string Merge(string s1, string s2) {
string s = "";
int i=0,j=0;
while(i<s1.size() && j<s2.size()) {
string q = s;
q.push_back(s1[i]);
for(int x=j; x<s2.size(); ++x) q.push_back(s2[x]);
if(query(q)==q.size()) {
s.push_back(s1[i++]);
} else {
s.push_back(s2[j++]);
}
}
while(i<s1.size()) s.push_back(s1[i++]);
while(j<s2.size()) s.push_back(s2[j++]);
return s;
}
string MergeSort(vector<string> t) {
if(t.size()==0) return "";
if(t.size()==1) return t[0];
vector<string> t1, t2;
int n =t.size();
for(int i=0; i<n/2; ++i) t1.push_back(t[i]);
for(int i=n/2; i<n; ++i) t2.push_back(t[i]);
return Merge(MergeSort(t1),MergeSort(t2));
}
string pwt(char c, int x) {
string s = "";
for(int i=0; i<x; ++i) s.push_back(c);
return s;
}
string guess(int n, int S) {
N=n;
string alph = "abcdefghijklmnopqrstuvwxyz";
vector<string> tab;
for(int i=0; i<S; ++i) {
tab.push_back(pwt(alph[i], query(pwt(alph[i],n))));
}
return MergeSort(tab);
}
