#include <bits/stdc++.h>
using namespace std;
template <class T>
bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
using V = vector<T>;
using P = pair<long long, long long>;
signed main() {
  long long n;
  cin >> n;
  string ans = "";
  for (long long i = (long long)(0); i < (long long)(n); i++) ans += "a";
  cout << ans << endl;
  for (long long i = n - 1; i > 0; i--) {
    for (long long j = (long long)(i); j < (long long)(n); j++) {
      ans[j]++;
      cout << ans << endl;
    }
  }
  return 0;
}
