#include "bits/stdc++.h"
using namespace std;
// #define int long long
// #define DEBUG 0
// #define MAX_QUERIES 50000
// #define MAX_N 5000
// #define MAX_SIGMA 26
// static string password;
// static int n, s, numQueries;
// static stringstream msg;
// static void end(int success) {
// cout << (success ? "SUCCESS! " : "ERROR: ") << msg.str() << endl;
// exit(0);
// }
// int query(string q) {
// if (++numQueries > MAX_QUERIES) {
// msg << "Could not guess the password with " << MAX_QUERIES << " questions.";
// end(0);
// }
// int len = q.size();
// // validation
// if (len < 1 || len > n) {
// msg << "Query '" << q << "' should have length between 1 and "
// << n << " characters.";
// end(0);
// }
// for (int i = 0; i < len; i++) {
// if (q[i] < 'a' || q[i] >= 'a' + s) {
// msg << "Illegal character '" << q[i] << "' found.";
// end(0);
// }
// }
// // while possible, advance one character in q and find its next
// // occurrence in password
// int i = 0, j = 0, plen = password.size();
// while (i < plen && j < len) {
// while ((i < plen) && (password[i] != q[j])) {
// i++;
// }
// if (i < plen) { /* found a match */
// i++;
// j++;
// }
// }
// if (DEBUG) {
// cout << "Question #" << numQueries << " [" << q << "] answer " << j << endl;
// }
// return j;
// }
int query(string s);
string guess(int n, int s){
array<int, 2>shi[30][30];
for(int i = 0; i < s; i++){
for(int j = i + 1; j < s; j++){
string a = "", b = "";
for(int k = 0; k < n; k++) a += (k % 2 ? j + 'a' : i + 'a');
for(int k = 0; k < n; k++) b += (k % 2 ? i + 'a' : j + 'a');
int ra = query(a), rb = query(b);
if(ra > rb) shi[i][j] = {ra, i};
else shi[i][j] = {rb, j};
}
}
string sk = "";
bool valid = 1;
int cnt[30][30] = {};
while(valid){
valid = 0;
bool idk[30];
for(int i = 0; i < 30; i++) idk[i] = 1;
for(int i = 0; i < s; i++){
for(int j = i + 1; j < s; j++){
if(cnt[i][j] >= shi[i][j][0]) continue;
valid = 1;
int f, se;
if(shi[i][j][1] == i){
f = i;
se = j;
}
else{
f = j;
se = i;
}
if(cnt[i][j] % 2 == 0) idk[se] = 0;
else idk[f] = 0;
}
}
if(!valid) continue;
for(int i = 0; i < s; i++){
if(idk[i]){
sk += i + 'a';
for(int j = i + 1; j < s; j++) cnt[i][j]++;
for(int j = 0; j < i; j++) cnt[j][i]++;
break;
}
}
}
if(s == 1) sk = 'a';
int cur = 0;
string ans = "";
for(int cur = 0; cur < sk.size(); cur++){
string fh = "", sh = "";
for(int i = 0; i < cur; i++) fh += sk[i];
for(int i = cur + 1; i < sk.size(); i++) sh += sk[i];
int l = 1, r = n - fh.size() - sh.size();
while(l <= r){
int mid = (l + r) / 2;
string tmp = "";
tmp += fh;
for(int i = 0; i < mid; i++) tmp += sk[cur];
tmp += sh;
return sk;
int a = query(tmp);
if(a != tmp.size()) r = mid - 1;
else l = mid + 1;
}
for(int i = 0; i < l - 1; i++) ans += sk[cur];
}
return ans;
}
// int main() {
// cin >> n >> s >> password;
// string answer = guess(n, s);
// if (DEBUG) {
// cout << "Your answer: [" << answer << "]\n";
// }
// if (answer.compare(password)) {
// msg << "Your answer was [" << answer
// << "] which does not match the password [" << password << "].";
// end(0);
// } else {
// msg << "You guessed the password with " << numQueries << " queries.";
// end(1);
// }
// return 0;
// }
