#include <bits/stdc++.h>
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
string S;
long long N;
vector<string> vs;
void dp(long long i = 0, string S = "") {
  if (S.length() == N) {
    vs.push_back(S);
    return;
  }
  S = S + to_string(i);
  long long max_n = -1;
  for (int i = 0; i < (int)(S.length()); i++) {
    if ((int)S[i] > max_n) {
      max_n = (int)S[i] - '0' + 1;
    }
  }
  for (int i = 0; i < (int)(max_n + 1); i++) {
    dp(i, S);
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> N;
  dp();
  vs.erase(unique(vs.begin(), vs.end()), vs.end());
  for (int j = 0; j < (int)(vs.size()); j++) {
    for (int i = 0; i < (int)(N); i++) {
      cout << char((int)(vs[j][i] - '0') + 'a');
    }
    cout << endl;
  }
  return 0;
}
