#include <bits/stdc++.h>
const double pi = 3.141592653589793238462643383279;
using namespace std;
inline int toInt(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T>
inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
inline int readInt() {
  int x;
  scanf("%d", &x);
  return x;
}
const double EPS = 1E-8;
class UnionFind {
 public:
  vector<int> par;
  vector<int> siz;
  UnionFind(int sz_) : par(sz_), siz(sz_, 1) {
    for (long long i = 0; i < sz_; ++i) par[i] = i;
  }
  void init(int sz_) {
    par.resize(sz_);
    siz.assign(sz_, 1LL);
    for (long long i = 0; i < sz_; ++i) par[i] = i;
  }
  int root(int x) {
    while (par[x] != x) {
      x = par[x] = par[par[x]];
    }
    return x;
  }
  bool merge(int x, int y) {
    x = root(x);
    y = root(y);
    if (x == y) return false;
    if (siz[x] < siz[y]) swap(x, y);
    siz[x] += siz[y];
    par[y] = x;
    return true;
  }
  bool issame(int x, int y) { return root(x) == root(y); }
  int size(int x) { return siz[root(x)]; }
};
long long modPow(long long x, long long n, long long mod = 1000000007) {
  if (n <= 0) return 1;
  long long res = 1;
  while (n) {
    if (n & 1) res = (res * x) % mod;
    res %= mod;
    x = x * x % mod;
    n >>= 1;
  }
  return res;
}
bool sieve[5000000 + 10];
void makeSieve() {
  for (int i = 0; i < 5000000 + 10; ++i) sieve[i] = true;
  sieve[0] = sieve[1] = false;
  for (int i = 2; i * i < 5000000 + 10; ++i)
    if (sieve[i])
      for (int j = 2; i * j < 5000000 + 10; ++j) sieve[i * j] = false;
}
bool isprime(long long n) {
  if (n == 0 || n == 1) return false;
  for (long long i = 2; i * i <= n; ++i)
    if (n % i == 0) return false;
  return true;
}
const int MAX = 2000010;
long long fac[MAX], finv[MAX], inv[MAX];
void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % 1000000007;
    inv[i] = 1000000007 - inv[1000000007 % i] * (1000000007 / i) % 1000000007;
    finv[i] = finv[i - 1] * inv[i] % 1000000007;
  }
}
long long COM(int n, int k) {
  if (n < k) return 0;
  if (n < 0 || k < 0) return 0;
  return fac[n] * (finv[k] * finv[n - k] % 1000000007) % 1000000007;
}
long long extGCD(long long a, long long b, long long &x, long long &y) {
  if (b == 0) {
    x = 1;
    y = 0;
    return a;
  }
  long long d = extGCD(b, a % b, y, x);
  y -= a / b * x;
  return d;
}
inline long long mod(long long a, long long m) { return (a % m + m) % m; }
long long modinv(long long a, long long m) {
  long long x, y;
  extGCD(a, m, x, y);
  return mod(x, m);
}
long long GCD(long long a, long long b) {
  if (b == 0) return a;
  return GCD(b, a % b);
}
int N;
void rec(string s, int i) {
  if (i == N) {
    cout << s << endl;
    return;
  }
  for (int j = 0; j <= s[s.size() - 1] - 'a' + 1; j++) {
    rec(s + (char)('a' + j), i + 1);
  }
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> N;
  rec("a", 1);
  return 0;
}
