#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
int main() {
  int n;
  cin >> n;
  for (int a = 0; a < 1; a++) {
    if (n == 1)
      cout << "a" << endl;
    else
      for (int b = 0; b < a + 2; b++) {
        if (n == 2)
          cout << "a" << char('a' + b) << endl;
        else
          for (int c = 0; c < b + 2; c++) {
            if (n == 3)
              cout << "a" << char('a' + b) << char('a' + c) << endl;
            else
              for (int d = 0; d < c + 2; d++) {
                if (n == 4)
                  cout << "a" << char('a' + b) << char('a' + c) << char('a' + d)
                       << endl;
                else
                  for (int e = 0; e < d + 2; e++) {
                    if (n == 5)
                      cout << "a" << char('a' + b) << char('a' + c)
                           << char('a' + d) << char('a' + e) << endl;
                    else
                      for (int f = 0; f < e + 2; f++) {
                        if (n == 6)
                          cout << "a" << char('a' + b) << char('a' + c)
                               << char('a' + d) << char('a' + e)
                               << char('a' + f) << endl;
                        else
                          for (int g = 0; g < f + 2; g++) {
                            if (n == 7)
                              cout << "a" << char('a' + b) << char('a' + c)
                                   << char('a' + d) << char('a' + e)
                                   << char('a' + f) << char('a' + g) << endl;
                            else
                              for (int h = 0; h < g + 2; h++) {
                                if (n == 8)
                                  cout << "a" << char('a' + b) << char('a' + c)
                                       << char('a' + d) << char('a' + e)
                                       << char('a' + f) << char('a' + g)
                                       << char('a' + h) << endl;
                                else
                                  for (int i = 0; i < h + 2; i++) {
                                    if (n == 9)
                                      cout << "a" << char('a' + b)
                                           << char('a' + c) << char('a' + d)
                                           << char('a' + e) << char('a' + f)
                                           << char('a' + g) << char('a' + h)
                                           << char('a' + i) << endl;
                                    else
                                      for (int j = 0; j < i + 2; j++) {
                                        if (n == 10)
                                          cout << "a" << char('a' + b)
                                               << char('a' + c) << char('a' + d)
                                               << char('a' + e) << char('a' + f)
                                               << char('a' + g) << char('a' + h)
                                               << char('a' + i) << char('a' + j)
                                               << endl;
                                      }
                                  }
                              }
                          }
                      }
                  }
              }
          }
      }
  }
}
