#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll, ll>;
using vl = vector<ll>;
using vvl = vector<vl>;
int main() {
  int N;
  cin >> N;
  vector<char> ans;
  for (int i = 0; i < (N); i++) {
    ans.push_back('a');
  }
  for (int i = 0; i < (N); i++) {
    for (int j = 0; j < (i); j++) ans.pop_back();
    for (int j = 0; j < (i); j++) ans.push_back('a' + j + 1);
    for (int k = 0; k < (N); k++) {
      cout << ans[k];
      if (k == N - 1) cout << endl;
    }
  }
}
