#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("Ofast")
constexpr ll INF = 1e18;
constexpr int inf = 1e9;
constexpr double INFD = 1e100;
constexpr ll mod = 1000000007;
constexpr ll mod2 = 998244353;
const double PI = 3.1415926535897932384626433832795028841971;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
vector<string> ans;
int N;
string S;
void f(int n, int now) {
  if (now == N) {
    set<char> se;
    for (int i = 0; i < N; i++) {
      se.insert(S[i]);
    }
    if (se.size() == n) {
      ans.push_back(S);
    }
  }
  set<char> se;
  for (int i = 0; i < now; i++) {
    se.insert(S[i]);
  }
  if (int(se.size()) + (N - now) < n) return;
  int mx = 0;
  for (int i = 0; i < now; i++) {
    chmax(mx, S[i] - 'a');
  }
  f(n, now + 1);
  for (int i = mx; i < n; i++) {
    S[now] += i;
    f(n, now + 1);
    S[now] -= i;
  }
}
int main() {
  cin >> N;
  S = string(N, 'a');
  for (int i = 1; i <= N; i++) {
    f(i, 1);
  }
  sort(ans.begin(), ans.end());
  ans.erase(unique(ans.begin(), ans.end()), ans.end());
  for (int i = 0; i < ans.size(); i++) {
    cout << ans[i] << '\n';
    ;
  }
  return 0;
}
