#include <bits/stdc++.h>
using namespace std;
inline bool setmin(int &x, int y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(int &x, int y) { return (y > x) ? x = y, 1 : 0; }
inline bool setmin(long long &x, long long y) { return (y < x) ? x = y, 1 : 0; }
inline bool setmax(long long &x, long long y) { return (y > x) ? x = y, 1 : 0; }
const int N = 100000;
const int inf = (int)1e9 + 1;
const long long big = (long long)1e18 + 1;
const int P = 239;
const int P1 = 31;
const int P2 = 57;
const int MOD = (int)1e9 + 7;
const int MOD1 = (int)1e9 + 9;
const int MOD2 = 998244353;
const long double eps = 1e-9;
const double pi = atan2(0, -1);
const int ABC = 26;
string s;
void rec(int rem, int c) {
  if (rem == 0) {
    cout << s << "\n";
    return;
  }
  for (int i = (0); i < (c + 2); i++) {
    s.push_back(char('a' + i));
    rec(rem - 1, i);
    s.pop_back();
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.precision(20);
  cout << fixed;
  int n;
  cin >> n;
  rec(n, -1);
  return 0;
}
