#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;
string guess(int n, int s);
int query(string str);
int cnt[350];
string guess(int n, int k)
{
vi ans;
vector<pair<int,char>> vsort;
rep2(z,'a','a'+k-1)
{
string s;
rep(i,n) s += (char)z;
cnt[z] = query(s);
vsort.pb({cnt[z],z});
}
sort(all(vsort));
forall(elm,vsort)
{
int c = elm.ff;
if(siz(ans) == 0)
{
rep(i,c) ans.pb(elm.ss);
continue;
}
vi ans2;
bool was_prev = 0;
for(int i = siz(ans)-1; i >= 0; i--)
{
if(!was_prev && i != 0 && c < i/2+1)
{
string q;
forall(it,ans2) q += (char)it;
q += (char)ans[i];
q += (char)ans[i-1];
rep(j,c) q += elm.ss;
reverse(all(q));
int l = query(q);
if(l == siz(q))
{
ans2.pb(ans[i]);
ans2.pb(ans[i-1]);
i--;
continue;
}
else was_prev = 1;
}
else was_prev = 0;
while(true)
{
string q;
forall(it,ans2) q += (char)it;
q += (char)ans[i];
rep(j,c) q += elm.ss;
reverse(all(q));
if(query(q) == siz(q)) break;
else
{
ans2.pb(elm.ss);
c--;
}
}
ans2.pb(ans[i]);
}
rep(j,c) ans2.pb(elm.ss);
reverse(all(ans2));
ans = ans2;
}
string str_ans;
forall(it,ans) str_ans += (char)it;
return str_ans;
}
