#include <bits/stdc++.h>
using namespace std;
const int mn = 1 * (int)(1e5) + 10;
const int mod = 1 * (int)(1e9) + 7;
const int mm = 1 * (int)(1e3) + 10;
const int base = 1 * (int)(1e9);
const bool aNs = 0;
int tt, ntest = 1;
void docfile() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  if (ifstream("test.inp")) {
    freopen("test.inp", "r", stdin);
    if (!aNs)
      freopen("test.out", "w", stdout);
    else
      freopen("test.ans", "w", stdout);
  } else if (ifstream("panasonic2020a.inp")) {
    freopen("panasonic2020a.inp", "r", stdin);
    freopen("panasonic2020a.out", "w", stdout);
  }
}
template <typename T>
void read(T& x) {
  x = 0;
  T f = 1;
  char ch = getchar();
  while (!isdigit(ch)) f = ch == '-' ? -f : f, ch = getchar();
  while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
  x *= f;
}
template <typename T>
void write(T a) {
  if (a < 0) {
    putchar('-');
    write(-a);
    return;
  }
  if (a < 10) {
    putchar('0' + a);
    return;
  }
  write(a / 10);
  putchar((char)('0' + (a % 10)));
}
int n;
vector<char> v;
vector<string> sol;
string s;
void genString(int k) {
  if (k == n) {
    cout << s << "\n";
    return;
  }
  for (char c = ((k && v[k] != v[k - 1]) ? v[k] : 'a'); c <= v[k]; ++c) {
    s.push_back(c);
    genString(k + 1);
    s.pop_back();
  }
}
void genArr(int k) {
  if (k == n) {
    genString(0);
    return;
  }
  for (int j = 0; j < 2; ++j) {
    if (j)
      v.emplace_back(v.back() + 1);
    else
      v.emplace_back(v.back());
    genArr(k + 1);
    v.pop_back();
  }
}
void enter() {
  cin >> n;
  v.emplace_back('a');
  genArr(1);
}
void solve() {}
void print_result() {}
int main() {
  docfile();
  for (tt = 1; tt <= ntest; ++tt) {
    enter();
    solve();
    print_result();
  }
}
