#include <bits/stdc++.h>
using namespace std;
using namespace std;
int main() {
  long long int N;
  scanf("%lld", &N);
  char S[11] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k'};
  char ans[100];
  long long int nowmax1 = 0, nowmax2 = 0, nowmax3 = 0, nowmax4 = 0, nowmax5 = 0,
                nowmax6 = 0, nowmax7 = 0, nowmax8 = 0, nowmax9 = 0,
                nowmax10 = 0;
  for (long long int a1 = 0; a1 <= 0; a1++) {
    nowmax1 = a1 + 1;
    if (N >= 2) {
      for (long long int a2 = 0; a2 <= nowmax1; a2++) {
        nowmax2 = max(a2 + 1, nowmax1);
        if (N >= 3) {
          for (long long int a3 = 0; a3 <= nowmax2; a3++) {
            nowmax3 = max(a3 + 1, nowmax2);
            if (N >= 4) {
              for (long long int a4 = 0; a4 <= nowmax3; a4++) {
                nowmax4 = max(a4 + 1, nowmax3);
                if (N >= 5) {
                  for (long long int a5 = 0; a5 <= nowmax4; a5++) {
                    nowmax5 = max(a5 + 1, nowmax4);
                    if (N >= 6) {
                      for (long long int a6 = 0; a6 <= nowmax5; a6++) {
                        nowmax6 = max(a6 + 1, nowmax5);
                        if (N >= 7) {
                          for (long long int a7 = 0; a7 <= nowmax6; a7++) {
                            nowmax7 = max(a7 + 1, nowmax6);
                            if (N >= 8) {
                              for (long long int a8 = 0; a8 <= nowmax7; a8++) {
                                nowmax8 = max(a8 + 1, nowmax7);
                                if (N >= 9) {
                                  for (long long int a9 = 0; a9 <= nowmax8;
                                       a9++) {
                                    nowmax9 = max(a9 + 1, nowmax8);
                                    if (N >= 10) {
                                      for (long long int a10 = 0;
                                           a10 <= nowmax9; a10++) {
                                        nowmax10 = max(a10 + 1, nowmax9);
                                        ans[0] = S[a1];
                                        ans[1] = S[a2];
                                        ans[2] = S[a3];
                                        ans[3] = S[a4];
                                        ans[4] = S[a5];
                                        ans[5] = S[a6];
                                        ans[6] = S[a7];
                                        ans[7] = S[a8];
                                        ans[8] = S[a9];
                                        ans[9] = S[a10];
                                        printf("%s \n", ans);
                                      }
                                    } else {
                                      ans[0] = S[a1];
                                      ans[1] = S[a2];
                                      ans[2] = S[a3];
                                      ans[3] = S[a4];
                                      ans[4] = S[a5];
                                      ans[5] = S[a6];
                                      ans[6] = S[a7];
                                      ans[7] = S[a8];
                                      ans[8] = S[a9];
                                      printf("%s \n", ans);
                                    }
                                  }
                                } else {
                                  ans[0] = S[a1];
                                  ans[1] = S[a2];
                                  ans[2] = S[a3];
                                  ans[3] = S[a4];
                                  ans[4] = S[a5];
                                  ans[5] = S[a6];
                                  ans[6] = S[a7];
                                  ans[7] = S[a8];
                                  printf("%s \n", ans);
                                }
                              }
                            } else {
                              ans[0] = S[a1];
                              ans[1] = S[a2];
                              ans[2] = S[a3];
                              ans[3] = S[a4];
                              ans[4] = S[a5];
                              ans[5] = S[a6];
                              ans[6] = S[a7];
                              printf("%s \n", ans);
                            }
                          }
                        } else {
                          ans[0] = S[a1];
                          ans[1] = S[a2];
                          ans[2] = S[a3];
                          ans[3] = S[a4];
                          ans[4] = S[a5];
                          ans[5] = S[a6];
                          printf("%s \n", ans);
                        }
                      }
                    } else {
                      ans[0] = S[a1];
                      ans[1] = S[a2];
                      ans[2] = S[a3];
                      ans[3] = S[a4];
                      ans[4] = S[a3];
                      printf("%s \n", ans);
                    }
                  }
                } else {
                  ans[0] = S[a1];
                  ans[1] = S[a2];
                  ans[2] = S[a3];
                  ans[3] = S[a4];
                  printf("%s \n", ans);
                }
              }
            } else {
              ans[0] = S[a1];
              ans[1] = S[a3];
              ans[2] = S[a3];
              printf("%s \n", ans);
            }
          }
        } else {
          ans[0] = S[a1];
          ans[1] = S[a2];
          printf("%s \n", ans);
        }
      }
    } else {
      ans[0] = S[a1];
      printf("%s \n", ans);
    }
  }
}
