#include <bits/stdc++.h>
using namespace std;
int query(string s);
string guess(int n, int s){
vector<string> res(s);
vector<int> val(s);
priority_queue<pair<int,int>> pq;
for(int i = 0; i < s; i++){
val[i] = query(string(n,char(i+'a')));
if(val[i]){
res[i] = string(val[i],char(i+'a'));
pq.push({val[i],i});
}
}
while(pq.size() > 1){
auto [l1,i] = pq.top(); pq.pop();
auto [l2,j] = pq.top(); pq.pop();
string tmp = res[j];
for(int k = 0, cur = 0; k < l1; k++){
tmp.insert(tmp.begin()+cur,res[i][k]);
if(query(tmp)==l2+k+1){
cur++;
}else{
swap(tmp[cur],tmp[cur+1]);
cur+=2;
}
}
res[i] = tmp;
val[i] = l1+l2;
pq.push({l1+l2,i});
}
auto [u,v] = pq.top();
return res[v];
}
