import std.stdio;
import std.string;
import std.format;
import std.conv;
import std.typecons;
import std.algorithm;
import std.functional;
import std.bigint;
import std.numeric;
import std.array;
import std.math;
import std.range;
import std.container;
import std.concurrency;
import std.traits;
import std.uni;
import std.regex;
import core.bitop : popcnt;
alias Generator = std.concurrency.Generator;

enum long INF = long.max/5;
enum long MOD = 10L^^9+7;

void main() {
  long N;
  scanln(N);

  long K = 26;
  long M = N*N;

  long[][] xss;
  void f(long d, long[] xs, long minC) {
    if (d == N) {
      xs.map!(x => (x+'a').to!char).writeln;
      return;
    }
    foreach(c; 0..min(minC+1, K)) {
      xs[d] = c;
      f(d+1, xs, max(minC, c+1));
    }
  }
  f(0, new long[N], 0);
}


struct UnionFind {

private:
  Vertex[] _vertices;
  size_t[] _sizes;

public:
  this(size_t n) {
    init(n);
  }

  void init(size_t n) {
    _vertices.length = n;
    _sizes.length = n;
    foreach(i, ref v; _vertices) {
      v.index = i;
      v.parent = i;
      _sizes[i] = 1;
    }
  }

  void unite(size_t x, size_t y) {
    link(findSet(x), findSet(y));
  }

  void link(size_t x, size_t y) {
    if (x==y) return;
    if (_vertices[x].rank > _vertices[y].rank) {
      _sizes[x] += _sizes[y];
      _vertices[y].parent = x;
    } else {
      _sizes[y] += _sizes[x];
      _vertices[x].parent = y;
      if (_vertices[x].rank == _vertices[y].rank) {
        _vertices[y].rank++;
      }
    }
  }

  bool same(size_t x, size_t y) {
    return findSet(x) == findSet(y);
  }

  size_t findSet(size_t index) {
    if (_vertices[index].parent == index) {
      return index;
    } else {
      return _vertices[index].parent = findSet(_vertices[index].parent);
    }
  }

  bool isRoot(size_t index) {
    return _vertices[index].parent == index;
  }

  size_t size(size_t index) {
    return _sizes[findSet(index)];
  }

private:
  struct Vertex {
    size_t index;
    size_t parent;
    size_t rank = 1;
  }
}


// ----------------------------------------------


void times(alias fun)(long n) {
  // n.iota.each!(i => fun());
  foreach(i; 0..n) fun();
}
auto rep(alias fun, T = typeof(fun()))(long n) {
  // return n.iota.map!(i => fun()).array;
  T[] res = new T[n];
  foreach(ref e; res) e = fun();
  return res;
}

T ceil(T)(T x, T y) if (isIntegral!T || is(T == BigInt)) {
  // `(x+y-1)/y` will only work for positive numbers ...
  T t = x / y;
  if (y > 0 && t * y < x) t++;
  if (y < 0 && t * y > x) t++;
  return t;
}

T floor(T)(T x, T y) if (isIntegral!T || is(T == BigInt)) {
  T t = x / y;
  if (y > 0 && t * y > x) t--;
  if (y < 0 && t * y < x) t--;
  return t;
}

ref T ch(alias fun, T, S...)(ref T lhs, S rhs) {
  return lhs = fun(lhs, rhs);
}
unittest {
  long x = 1000;
  x.ch!min(2000);
  assert(x == 1000);
  x.ch!min(3, 2, 1);
  assert(x == 1);
  x.ch!max(100).ch!min(1000); // clamp
  assert(x == 100);
  x.ch!max(0).ch!min(10); // clamp
  assert(x == 10);
}

mixin template Constructor() {
  import std.traits : FieldNameTuple;
  this(Args...)(Args args) {
    // static foreach(i, v; args) {
    foreach(i, v; args) {
      mixin("this." ~ FieldNameTuple!(typeof(this))[i]) = v;
    }
  }
}

void scanln(Args...)(auto ref Args args) {
  enum sep = " ";
  enum n = Args.length;
  enum fmt = n.rep!(()=>"%s").join(sep);

  string line = readln.chomp;
  static if (__VERSION__ >= 2074) {
    line.formattedRead!fmt(args);
  } else {
    enum argsTemp = n.iota.map!(
      i => "&args[%d]".format(i)
    ).join(", ");
    mixin(
      "line.formattedRead(fmt, " ~ argsTemp ~ ");"
    );
  }
}

// fold was added in D 2.071.0
static if (__VERSION__ < 2071) {
  template fold(fun...) if (fun.length >= 1) {
    auto fold(R, S...)(R r, S seed) {
      static if (S.length < 2) {
        return reduce!fun(seed, r);
      } else {
        return reduce!fun(tuple(seed), r);
      }
    }
  }
}

// popcnt with ulongs was added in D 2.071.0
static if (__VERSION__ < 2071) {
  ulong popcnt(ulong x) {
    x = (x & 0x5555555555555555L) + (x>> 1 & 0x5555555555555555L);
    x = (x & 0x3333333333333333L) + (x>> 2 & 0x3333333333333333L);
    x = (x & 0x0f0f0f0f0f0f0f0fL) + (x>> 4 & 0x0f0f0f0f0f0f0f0fL);
    x = (x & 0x00ff00ff00ff00ffL) + (x>> 8 & 0x00ff00ff00ff00ffL);
    x = (x & 0x0000ffff0000ffffL) + (x>>16 & 0x0000ffff0000ffffL);
    x = (x & 0x00000000ffffffffL) + (x>>32 & 0x00000000ffffffffL);
    return x;
  }
}


Measured memory_bytes: 1532