import java.util.Scanner;
public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        int N = sc.nextInt();
        
        char[] s1 = "aaaaaz".toCharArray();
        char[] s2 = "zaaaaa".toCharArray();
        
        if (N == 1) {
        	System.out.println("n");
        	return;
        }
        
        int count = 0;
        for (char i1 = 'a'; i1 <= 'z'; i1++) {
        	for (char i2 = 'a'; i2 < 'z'; i2++) {
        		for (char i3 = 'a'; i3 < 'z'; i3++) {
        			for (char i4 = 'a'; i4 < 'z'; i4++) {
        				if (count % 2 == 0) {
        					s1[1] = i1;
        					s1[2] = i2;
        					s1[3] = i3;
        					s1[4] = i4;
        					System.out.println(new String(s1));
        				} else {
        					s2[1] = i1;
        					s2[2] = i2;
        					s2[3] = i3;
        					s2[4] = i4;
        					System.out.println(new String(s2));
        				}
        				
        				count++;
        				if (count == N-1) {
        					System.out.println(count % 2 == 0 ? "an": "zn");
        					return;
        				}
        			}
        		}
        	}
        }

    }
}