#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll LINF = 0x1fffffffffffffff;
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
int main() {
  ll N;
  cin >> N;
  vector<string> tbl;
  string tmp;
  for (ll i = (0); i < (N); ++i) {
    tmp.push_back('a');
  }
  cout << tmp << endl;
  for (ll j = (1); j < (N); ++j) {
    for (ll i = (0); i < (N - j); ++i) {
      ll pos = N - 1 - i;
      tmp.at(pos) = ((char)'a' + j);
      cout << tmp << endl;
    }
  }
  return 0;
}
