import java.util.Scanner;
import java.util.regex.*;
public class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    String str = sc.nextLine();
    
    if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a');
  }
} import java.util.Scanner; Scanner java.util import java.util.regex.*; regex.* java.util public class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    String str = sc.nextLine();
    
    if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a');
  }
} Main public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    String str = sc.nextLine();
    
    if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a');
  } main {
    Scanner sc = new Scanner(System.in);
    String str = sc.nextLine();
    
    if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a');
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String str = sc.nextLine(); str sc.nextLine() sc.nextLine sc if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a'); Pattern.matches("[A-Z]",str) Pattern.matches Pattern "[A-Z]" str System.out.println('A') System.out.println System.out System System.out '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 sc = new Scanner(System.in);
    String str = sc.nextLine();
    
    if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a');
  }
} public class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    String str = sc.nextLine();
    
    if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a');
  }
} Main
import java.util.Scanner;
import java.util.regex.*;
public class Main
{
  public static void main(String[] args)
  {
    Scanner sc = new Scanner(System.in);
    String str = sc.nextLine();
    
    if(Pattern.matches("[A-Z]",str))
      System.out.println('A');
      else
        System.out.println('a');
  }
}
