import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;

public class Main {

	static PrintWriter out;
	static InputReader ir;

	static void solve() {
		int n = ir.nextInt();
		String[] res = dfs(n);
		Arrays.sort(res);
		for (int i = 0; i < res.length; i++) {
			out.println(res[i]);
		}
	}

	static String[] dfs(int x) {
		if (x == 0) {
			return new String[] {};
		}
		if (x == 1) {
			return new String[] { "a" };
		}
		String[] s = dfs(x - 1);
		HashSet<String> st = new HashSet<>();
		for (int i = 0; i < s.length; i++) {
			st.add("a" + s[i]);
		}
		for (int i = 0; i < s.length; i++) {
			char[] t = s[i].toCharArray();
			for (int j = 0; j < t.length; j++) {
				t[j]++;
			}
			st.add("a" + String.valueOf(t));
		}
		char[] u = new char[x];
		for (int i = 2; i < x; i++) {
			u[0] = 'a';
			String[] p = dfs(x - i);
			String[] q = dfs(i - 1);
			for (int j = 0; j < p.length; j++) {
				for (int k = i; k < x; k++) {
					u[k] = p[j].charAt(k - i);
				}
				for (int k = 0; k < q.length; k++) {
					for (int l = 1; l < i; l++) {
						u[l] = (char) (q[k].charAt(l - 1) + 1);
					}
					st.add(String.valueOf(u));
				}
			}
		}
		ArrayList<String> l = new ArrayList<>(st);
		String[] res = new String[st.size()];
		for (int i = 0; i < res.length; i++)
			res[i] = l.get(i);
		return res;
	}

	public static void main(String[] args) {
		ir = new InputReader(System.in);
		out = new PrintWriter(System.out);
		solve();
		out.flush();
	}

	static class InputReader {

		private InputStream in;
		private byte[] buffer = new byte[1024];
		private int curbuf;
		private int lenbuf;

		public InputReader(InputStream in) {
			this.in = in;
			this.curbuf = this.lenbuf = 0;
		}

		public boolean hasNextByte() {
			if (curbuf >= lenbuf) {
				curbuf = 0;
				try {
					lenbuf = in.read(buffer);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (lenbuf <= 0)
					return false;
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[curbuf++];
			else
				return -1;
		}

		private boolean isSpaceChar(int c) {
			return !(c >= 33 && c <= 126);
		}

		private void skip() {
			while (hasNextByte() && isSpaceChar(buffer[curbuf]))
				curbuf++;
		}

		public boolean hasNext() {
			skip();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (!isSpaceChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public int nextInt() {
			if (!hasNext())
				throw new NoSuchElementException();
			int c = readByte();
			while (isSpaceChar(c))
				c = readByte();
			boolean minus = false;
			if (c == '-') {
				minus = true;
				c = readByte();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res = res * 10 + c - '0';
				c = readByte();
			} while (!isSpaceChar(c));
			return (minus) ? -res : res;
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			int c = readByte();
			while (isSpaceChar(c))
				c = readByte();
			boolean minus = false;
			if (c == '-') {
				minus = true;
				c = readByte();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res = res * 10 + c - '0';
				c = readByte();
			} while (!isSpaceChar(c));
			return (minus) ? -res : res;
		}

		public double nextDouble() {
			return Double.parseDouble(next());
		}

		public int[] nextIntArray(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextLongArray(int n) {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public char[][] nextCharMap(int n, int m) {
			char[][] map = new char[n][m];
			for (int i = 0; i < n; i++)
				map[i] = next().toCharArray();
			return map;
		}
	}

	static void tr(Object... o) {
		out.println(Arrays.deepToString(o));
		out.flush();
	}
}
