#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;
int getQ(string s) {
if(s.size() > N) return N+20;
return query(s);
}
string guess(int n, int S) {
N=n;
vector<int> cnt(S);
string alph = "abcdefghijklmnopqrstuvwxyz";
vector<int> V;
for(int i=0; i<S; ++i) {
string s = "";
s.push_back(alph[i]);
while(getQ(s)==s.size()) s.push_back(alph[i]);
cnt[i] = s.size() - 1;
if(cnt[i]) V.push_back(i);
}
sort(V.begin(), V.end(), [&](int a, int b){
string s(cnt[a], alph[a]);
s.push_back(alph[b]);
if(getQ(s)==s.size()) return true;
return false;
});
string res = "", stos="";
res.push_back(alph[V.back()]);
for(int i=res.size()-1; i>=0; --i) {
for(int lit : V) {
string old_res = res;
stos = "";
for(int x=res.size()-1; x>=i; --x) {
stos.push_back(res[x]);
res.pop_back();
}
reverse(stos.begin(), stos.end());
res.push_back(alph[lit]);
res += stos;
if(getQ(res)!=res.size()) {
res = old_res;
} else i++;
}
}
return res;
}
