#include <bits/stdc++.h>
using namespace std;
long long power_mod(long long num, long long g) {
  if (g == 0) return 1;
  if (g % 2 == 1)
    return (num * power_mod((num * num) % 1000000007, g / 2)) % 1000000007;
  return power_mod((num * num) % 1000000007, g / 2);
}
long long power(long long num, long long g) {
  if (g == 0) return 1;
  if (g % 2 == 1) return (num * power((num * num), g / 2));
  return power((num * num), g / 2);
}
void solve(long long x, vector<char> vec) {
  if (x == 0) {
    for (long long i = 0; i < vec.size(); i++) cout << vec[i];
    cout << endl;
    return;
  }
  if (vec.empty()) {
    vec.push_back('a');
    solve(x - 1, vec);
    return;
  }
  long long l = vec.size();
  vec.push_back(vec[l - 1]);
  solve(x - 1, vec);
  vec.pop_back();
  vec.push_back(vec[l - 1] + 1);
  solve(x - 1, vec);
  vec.pop_back();
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long x = 3;
  cin >> x;
  vector<char> vec;
  solve(x, vec);
  return 0;
}
