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

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        StringBuilder sb = new StringBuilder();
        char[] tmp = new char[10];
        tmp[0] = 'a';
        tmp[9] = 'a';
        for (int i = 0; i < n - 1; i++) {
            int x = i;
            for (int j = 0; j < 8; j++) {
                tmp[j + 1] = (char)(x % 26 + 'a');
                x /= 26;
            }
            sb.append(new String(tmp)).append("\n");
        }
        System.out.print(sb);
        System.out.println("an");
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}