#include <bits/stdc++.h>
using namespace std;
priority_queue<pair<long long, long long>, vector<pair<long long, long long> >,
               greater<pair<long long, long long> > >
    pq;
priority_queue<long long, vector<long long>, greater<long long> > pq1;
long long dp[2010][2010];
long long a[2010];
long long H;
long long n, l, r;
int main() {
  if (fopen("input.txt", "r"))
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n;
  cin >> n;
  string s = "";
  for (int i = 0; i < n; i++) s += "a";
  long long i = n - 2;
  long long j = n - 1;
  cout << s << "\n";
  while (i >= 0) {
    if (i == j) {
      i--;
      j = n - 1;
      continue;
    }
    if (s[j] == 'z') {
      j--;
      continue;
    }
    s[j] = s[j] + 1;
    cout << s << "\n";
    j--;
  }
  return 0;
}
