using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Panasonic2020D
{
    class Input
    {
        /// <summary>
        /// 1行の入力を取得する
        /// </summary>
        /// <returns>文字列</returns>
        public void String(out string s)
        {
            s = Console.ReadLine();
        }

        /// <summary>
        /// 複数行の入力を取得
        /// </summary>
        /// <returns>文字列の配列</returns>
        public void String(long rowNumber, out string[] s)
        {
            s = new String[rowNumber];
            for (long i = 0; i < rowNumber; i++)
            {
                String(out s[i]);
            }
        }

        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <returns>int型の値</returns>
        public void Int(out int i)
        {
            string s;
            String(out s);
            i = int.Parse(s);
        }

        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <param name="a"></param>
        public void Long(out long a)
        {
            string s;
            String(out s);
            a = long.Parse(s);
        }

        /// <summary>
        /// 2つの整数が1行に書かれている入力を、2つのlongで受け取る
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        public void Long(out long a, out long b)
        {
            long[] lArr;
            Long(out lArr);
            a = lArr[0];
            b = lArr[1];
        }

        /// <summary>
        /// 3つの整数が1行に書かれている入力を、3つのlongで受け取る
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        public void Long(out long a, out long b, out long c)
        {
            long[] lArr;
            Long(out lArr);
            a = lArr[0];
            b = lArr[1];
            c = lArr[2];
        }

        /// <summary>
        /// 4つの整数が1行に書かれている入力を、4つのlongで受け取る
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        /// <param name="d"></param>
        public void Long(out long a, out long b, out long c, out long d)
        {
            long[] lArr;
            Long(out lArr);
            a = lArr[0];
            b = lArr[1];
            c = lArr[2];
            d = lArr[3];
        }

        public void Long(out long[] lArr)
        {
            lArr = Split().Select(long.Parse).ToArray();
        }

        public void Long(long rowNumber, out long[] lArr)
        {
            lArr = new long[rowNumber];
            for (long i = 0; i < rowNumber; i++)
            {
                Long(out lArr[i]);
            }
        }

        /// <summary>
        /// 2つの整数が複数行に書かれている入力を、2つのlong[]で受け取る
        /// </summary>
        /// <param name="rowNumber"></param>
        /// <param name="a"></param>
        /// <param name="b"></param>
        public void Long(long rowNumber, out long[] a, out long[] b)
        {
            a = new long[rowNumber];
            b = new long[rowNumber];
            for (int i = 0; i < rowNumber; i++)
            {
                Long(out a[i], out b[i]);
            }
        }

        /// <summary>
        /// 3つの整数が複数行に書かれている入力を、3つのlong[]で受け取る
        /// </summary>
        /// <param name="rowNumber"></param>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        public void Long(long rowNumber, out long[] a, out long[] b, out long[] c)
        {
            a = new long[rowNumber];
            b = new long[rowNumber];
            c = new long[rowNumber];
            for (int i = 0; i < rowNumber; i++)
            {
                Long(out a[i], out b[i], out c[i]);
            }
        }

        /// <summary>
        /// 4つの整数が複数行に書かれている入力を、4つのlong[]で受け取る
        /// </summary>
        /// <param name="rowNumber"></param>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        /// <param name="d"></param>
        public void Long(long rowNumber, out long[] a, out long[] b, out long[] c, out long[] d)
        {
            a = new long[rowNumber];
            b = new long[rowNumber];
            c = new long[rowNumber];
            d = new long[rowNumber];
            for (int i = 0; i < rowNumber; i++)
            {
                Long(out a[i], out b[i], out c[i], out d[i]);
            }
        }

        /// <summary>
        /// h行w列のLongのmapを入力する
        /// </summary>
        /// <param name="h"></param>
        /// <param name="w"></param>
        /// <param name="a"></param>
        public void Long(long h, long w, out long[][] a)
        {
            a = new long[h][];
            for (long i = 0; i < h; i++)
            {
                Long(out a[i]);
            }
        }

        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <returns>double型の値</returns>
        public void Double(out double d)
        {
            string s;
            String(out s);
            d = double.Parse(s);
        }

        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <returns>double型の配列</returns>
        public void Double(out double[] dArr)
        {
            dArr = Split().Select(double.Parse).ToArray();
        }

        private IEnumerable<string> Split()
        {
            string s;
            String(out s);
            return s.Split(' ');
        }
    }

    class Program
    {
        public static void Main(string[] args)
        {
            StreamWriter sw = new StreamWriter(Console.OpenStandardOutput()) {AutoFlush = false};
            //  Console.SetOut(sw);
            Solver solver = new Solver();
            solver.Solve();
            //  Console.Out.Flush();
        }
    }

    class Solver
    {
        private Input input;

        public Solver()
        {
            input = new Input();
            input.Long(out N);
        }

        private long N;

        public void Solve()
        {
            if (N == 1)
            {
                Console.WriteLine("a");
                return;
            }

            write((int) N, 1, 1, 0);
            foreach (string a in ans)
            {
                Console.WriteLine(a.Substring(0, (int) N));
            }
        }

        private List<String> ans = new List<string>();

        public void write(
            int max,
            int depth,
            int chars,
            int a1,
            int a2 = 0,
            int a3 = 0,
            int a4 = 0,
            int a5 = 0,
            int a6 = 0,
            int a7 = 0,
            int a8 = 0,
            int a9 = 0,
            int a10 = 0
        )
        {
            if (max == depth)
            {
                char[] s =
                {
                    (char) (a1 + 'a'),
                    (char) (a2 + 'a'),
                    (char) (a3 + 'a'),
                    (char) (a4 + 'a'),
                    (char) (a5 + 'a'),
                    (char) (a6 + 'a'),
                    (char) (a7 + 'a'),
                    (char) (a8 + 'a'),
                    (char) (a9 + 'a'),
                    (char) (a10 + 'a'),
                };
                ans.Add(new string(s));
                return;
            }

            //Console.WriteLine('a' + a.Length);
            for (int c = 0; c < chars + 1; c++)
            {
                var cs = Math.Max(chars, c + 1);
                if (depth == 1)
                {
                    write(max, depth + 1, cs, a1, c);
                }
                else if (depth == 2)
                {
                    write(max, depth + 1, cs, a1, a2, c);
                }
                else if (depth == 3)
                {
                    write(max, depth + 1, cs, a1, a2, a3, c);
                }
                else if (depth == 4)
                {
                    write(max, depth + 1, cs, a1, a2, a3, a4, c);
                }
                else if (depth == 5)
                {
                    write(max, depth + 1, cs, a1, a2, a3, a4, a5, c);
                }
                else if (depth == 6)
                {
                    write(max, depth + 1, cs, a1, a2, a3, a4, a5, a6, c);
                }
                else if (depth == 7)
                {
                    write(max, depth + 1, cs, a1, a2, a3, a4, a5, a6, a7, c);
                }
                else if (depth == 8)
                {
                    write(max, depth + 1, cs, a1, a2, a3, a4, a5, a6, a7, a8, c);
                }
                else if (depth == 9)
                {
                    write(max, depth + 1, cs, a1, a2, a3, a4, a5, a6, a7, a8, a9, c);
                }
            }
        }
    }
}

Measured memory_bytes: 23760