#include "bits/stdc++.h"

using namespace std;

#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define rep1(i,n) for(ll i=1;i<=(ll)(n);i++)
#define rrep(i,n) for(ll i=(ll)(n)-1;i>=0;i--)
#define rrep1(i,n) for(ll i=(ll)(n);i>0;i--)
#define REP(i,a,b) for(ll i=(ll)a;i<(ll)b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
const ll inf = 1000000001;
const ll INF = 2e18;
const ll MOD = 1000000007;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { 1,0, -1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);

int solve1();
int solve2();
int solve3();

int main () {
  solve2();
}

int solve1() {
  int n, m;
  cin >> n >> m;
  vs s(n);
  rep (i, n) {
    cin >> s[i];
  }
  rep (i, n) {
    rep (j, m - 3) {
      if (s[i].substr(j, 4) == "LOVE") {
        cout << "YES" << endl;
        return 0;
      }
    }
  }
  cout << "NO" << endl;
  return 0;
}

int solve2() {
  int n;
  cin >> n;
  random_device rnd;
  mt19937 mt(rnd());
  uniform_int_distribution<> rand(0, 25);
  set<string> st;
  char head = 'a';
  while (n--) {
    string s;
    s.push_back(head);
    if (n) {
      rep (i, 19) {
        int j = rand(mt);
        char c = 'a' + j;
        if (i == 18 && c == 'n') {
          i--;
          continue;
        }
        s.push_back(c);
      }
    }
    else {
      rep (i, 18) {
        int j = rand(mt);
        char c = 'a' + j;
        s.push_back(c);
      }
      s.push_back('n');
    }
    if (st.count(s)) {
      n++;
    }
    else {
      cout << s << endl;
      head = s.back();
    }
  }
}

uint32_t x = 0, y = 1, z = 2, w = 3;
uint32_t MAX = UINT_MAX;

uint32_t generate() {
  uint32_t t = (x ^ (x << 11));
  x = y; y = z; z = w;
  w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
  return w;
}

int solve3() {
  int64_t seed; cin >> seed;
  x = seed;
  int smallcnt = 0;
  vector<uint32_t> a;
  rep (i, 10000001) {
    uint32_t temp = generate();
    if (temp < MAX / 4) {
      smallcnt++;
    }
    else if (temp < MAX * 3 / 4) {
      a.push_back(temp);
    }
  }
  sort(all(a));
  assert(smallcnt <= 10000001 / 2);
  cout << a[10000001 / 2 - smallcnt] << endl;
}