package 蓝桥杯试题;
import java.util.Scanner;
public class Fj {
static int n;
static String a[];
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc=new Scanner(System.in);
n=sc.nextInt();
String[] a=new String[n];
a[0]="A";
for(int i=1;i<n;i++) {
char f=(char) (65+i);
a[i]=a[i-1]+f+a[i-1];
}
System.out.println(a[n-1]);
}
}
import java.util.Scanner;
public class Fj {
static int n;
static String a[];
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc=new Scanner(System.in);
n=sc.nextInt();
String[] a=new String[n];
a[0]="A";
for(int i=1;i<n;i++) {
char f=(char) (65+i);
a[i]=a[i-1]+f+a[i-1];
}
System.out.println(a[n-1]);
}
}