#include <bits/stdc++.h>
using namespace std;
using ll = long long int;
int rekkyo(string str, int rest) {
  if (rest == 0) {
    cout << str << endl;
    return 0;
  }
  string next_str1 = str + str[str.size() - 1];
  rekkyo(next_str1, rest - 1);
  string next_str2 = str + (char)(str[str.size() - 1] + 1);
  rekkyo(next_str2, rest - 1);
  return 0;
}
int main(int argc, char *argv[]) {
  int n;
  cin >> n;
  string ans = "a";
  rekkyo(ans, n - 1);
  return 0;
}
