import java.util.*;

public class Main {
	public static void main (String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int n = sc.nextInt();
    	StringBuilder sb = new StringBuilder();
    	for (int i = 0; i < n - 1; i++) {
    	    sb.append('a');
    	    int count = i;
    	    while (count > 0) {
    	        sb.append((char)('a' + count % 26));
    	        count /= 26;
    	    }
    	    sb.append('a').append("\n");
    	}
    	sb.append("an");
    	System.out.println(sb);
	}
}