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

public class Main{
	public static void main(String[] args){
    	Scanner s = new Scanner(System.in);
      	char c = s.next().charAt(0);
      	if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        }}} import java.io.*; io.* java import java.util.*; util.* java public class Main{
	public static void main(String[] args){
    	Scanner s = new Scanner(System.in);
      	char c = s.next().charAt(0);
      	if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        }}} Main public static void main(String[] args){
    	Scanner s = new Scanner(System.in);
      	char c = s.next().charAt(0);
      	if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        }} main {
    	Scanner s = new Scanner(System.in);
      	char c = s.next().charAt(0);
      	if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        }} Scanner s = new Scanner(System.in); s new Scanner(System.in) char c = s.next().charAt(0); c s.next().charAt(0) s.next().charAt s.next() s.next s 0 if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        } Character.isUpperCase(c) Character.isUpperCase Character c {
          	System.out.println('A');
        } System.out.println('A') System.out.println System.out System System.out 'A' {
          System.out.println('a');
        } System.out.println('a') System.out.println System.out System System.out 'a' String[] args args public class Main{
	public static void main(String[] args){
    	Scanner s = new Scanner(System.in);
      	char c = s.next().charAt(0);
      	if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        }}} public class Main{
	public static void main(String[] args){
    	Scanner s = new Scanner(System.in);
      	char c = s.next().charAt(0);
      	if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        }}} Main
import java.io.*;
import java.util.*;

public class Main{
	public static void main(String[] args){
    	Scanner s = new Scanner(System.in);
      	char c = s.next().charAt(0);
      	if (Character.isUpperCase(c)){
          	System.out.println('A');
        }else{
          System.out.println('a');
        }}}
