#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
const int inf = 1001001001;
void write(string s, int n) {
  if (n == 0) {
    cout << s << endl;
    return;
  }
  char c = s[s.size() - 1];
  char nc = c + 1;
  string ns1 = s + c;
  string ns2 = s + nc;
  write(ns1, n - 1);
  write(ns2, n - 1);
}
int main() {
  int n;
  cin >> n;
  write("a", n - 1);
}
