#include <bits/stdc++.h>
using ll = long long;
using ull = unsigned long long;
constexpr int INF = 1073741823;
constexpr int MINF = -1073741823;
constexpr ll LINF = ll(4661686018427387903);
constexpr ll MOD = 1e9 + 7;
constexpr long double eps = 1e-6;
const long double PI = acosl(-1.0L);
using namespace std;
void scans(string& str) {
  char c;
  str = "";
  scanf("%c", &c);
  if (c == '\n') scanf("%c", &c);
  while (c != '\n' && c != -1 && c != ' ') {
    str += c;
    scanf("%c", &c);
  }
}
void scanc(char& str) {
  char c;
  scanf("%c", &c);
  if (c == -1) return;
  while (c == '\n') {
    scanf("%c", &c);
  }
  str = c;
}
double acot(double x) { return PI / 2 - atan(x); }
ll LSB(ll n) { return (n & (-n)); }
template <typename T>
T chmin(T& a, const T& b) {
  if (a > b) a = b;
  return a;
}
template <typename T>
T chmax(T& a, const T& b) {
  if (a < b) a = b;
  return a;
}
void dfs(const int& cnt, const int& n, string s) {
  if (cnt + 1 == n) {
    printf("%s\n", s.c_str());
    return;
  }
  dfs(cnt + 1, n, s + char(s.back()));
  dfs(cnt + 1, n, s + char(s.back() + 1));
}
int main() {
  int n;
  scanf("%d", &n);
  dfs(0, n, "a");
  return 0;
}
