import java.util.Scanner;
public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        int N = sc.nextInt();
        
        char[] s = "aaaaaaaaaaaaaaaaaaaz".toCharArray();
        
        int index = 1;
        for (int i = 0; i < N-1; i++) {
        	if (s[index] == 'z') {
        		index++;
        		s[index]++;
        	} else {
        		s[index]++;
        	}
        	
        	if (i % 2 == 0) {
        		System.out.println(new String(s));
        	} else {
        		for (int j = s.length-1; 0 <= j; j--) {
        			System.out.print(s[j]);
        		}
        		System.out.println();
        	}
        }
        
        s[s.length-1] = 'n';
        System.out.println(new String(s));
    }
}