import java.io.*;
import java.io.IOException;
import java.util.*;

@SuppressWarnings({"rawtypes", "unchecked"})
class Main {
    final static int INF = 1 << 28;
    final static long LNF = 1L << 60;
    final static double EPS = 1e-9;
    final static double GOLDEN_RATIO = (1.0 + Math.sqrt(5)) / 2.0;
    static int N;

    static final long MOD = 1_000_000_007;

    public static void main(String[] args) throws Exception {
        final MyScanner sc = new MyScanner();
        N = sc.nextInt();
        solve();
    }

    static void solve(){
        ArrayList<Character> ca = new ArrayList<>();
        ca.add('a');
        dfs(ca);
    }
    
    public static void dfs(ArrayList<Character> ca){
        if(ca.size()== N) {
            StringBuilder sb = new StringBuilder();
            for (Character character : ca) {
                sb.append(character);
            }
            System.out.println(sb.toString());
            return;
        } 

        int maxc = 0;
        for (char c: ca) {
            maxc = Math.max(maxc, (int)c);
        }
        for (int i = 'a'; i <= maxc+1; i++) {
            ca.add((char)i);
            dfs(ca);
            ca.remove(ca.size()-1);
        }
    }


    static class MyScanner {
 
        BufferedReader br;
        StringTokenizer st;
 
        MyScanner(FileReader fileReader) {
            br = new BufferedReader(fileReader);
        }
 
        MyScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String nn() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        String next() {
            return nn();
        }

        String nextLine() {
            String ans = "";
            try {
                ans = br.readLine();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            return ans;
        }
 
        char nextChar() {
            return nn().charAt(0);
        }
 
        int nextInt() {
            return Integer.parseInt(nn());
        }
 
        long nextLong() {
            return Long.parseLong(nn());
        }
 
        double nextDouble() {
            return Double.parseDouble(nn());
        }
 
        Integer[] niArr0(int n) {
            Integer[] ar = new Integer[n];
            for (int i = 0; i < n; i++) {
                ar[i] = nextInt();
            }
            return ar;
        }
 
        Integer[] niArr1(int n) {
            Integer[] ar = new Integer[n + 1];
            for (int i = 1; i <= n; i++) {
                ar[i] = nextInt();
            }
            return ar;
        }
 
        Long[] nlArr0(int n) {
            Long[] ar = new Long[n];
            for (int i = 0; i < n; i++) {
                ar[i] = nextLong();
            }
            return ar;
        }
 
        Long[] nlArr1(int n) {
            Long[] ar = new Long[n + 1];
            for (int i = 1; i <= n; i++) {
                ar[i] = nextLong();
            }
            return ar;
        }
    }

}


Measured memory_bytes: 69288