#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<char> v = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'};
  string abc = "abcdefghij";
  int N;
  cin >> N;
  for (int i = 0; i < N; i++) {
    string ans = abc.substr(0, i + 1);
    if (ans.size() == N) {
      cout << ans << endl;
      break;
    }
    for (int a = 0; a < i + 1; a++) {
      if (ans.size() + 1 > N) break;
      for (int b = 0; b < i + 1; b++) {
        if (ans.size() + 2 > N) break;
        for (int c = 0; c < i + 1; c++) {
          if (ans.size() + 3 > N) break;
          for (int d = 0; d < i + 1; d++) {
            if (ans.size() + 4 > N) break;
            for (int e = 0; e < i + 1; e++) {
              if (ans.size() + 5 > N) break;
              for (int f = 0; f < i + 1; f++) {
                if (ans.size() + 6 > N) break;
                for (int g = 0; g < i + 1; g++) {
                  if (ans.size() + 7 > N) break;
                  for (int h = 0; h < i + 1; h++) {
                    if (ans.size() + 8 > N) break;
                    for (int j = 0; j < i + 1; j++) {
                      if (ans.size() + 9 > N) break;
                      if (ans.size() + 9 == N)
                        cout << ans + abc[a] + abc[b] + abc[c] + abc[d] +
                                    abc[e] + abc[f] + abc[g] + abc[h] + abc[j]
                             << endl;
                    }
                    if (ans.size() + 8 == N)
                      cout << ans + abc[a] + abc[b] + abc[c] + abc[d] + abc[e] +
                                  abc[f] + abc[g] + abc[h]
                           << endl;
                  }
                  if (ans.size() + 7 == N)
                    cout << ans + abc[a] + abc[b] + abc[c] + abc[d] + abc[e] +
                                abc[f] + abc[g]
                         << endl;
                }
                if (ans.size() + 6 == N)
                  cout << ans + abc[a] + abc[b] + abc[c] + abc[d] + abc[e] +
                              abc[f]
                       << endl;
              }
              if (ans.size() + 5 == N)
                cout << ans + abc[a] + abc[b] + abc[c] + abc[d] + abc[e]
                     << endl;
            }
            if (ans.size() + 4 == N)
              cout << ans + abc[a] + abc[b] + abc[c] + abc[d] << endl;
          }
          if (ans.size() + 3 == N)
            cout << ans + abc[a] + abc[b] + abc[c] << endl;
        }
        if (ans.size() + 2 == N) cout << ans + abc[a] + abc[b] << endl;
      }
      if (ans.size() + 1 == N) cout << ans + abc[a] << endl;
    }
  }
  return 0;
}
