import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
			Scanner s= new Scanner(System.in);
		  char s1= s.next().charAt(0);
		  
		  if(s1 >='A' && s1 <= 'Z')
		    System.out.println("A");
		   else
		  	System.out.println("a");
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
			Scanner s= new Scanner(System.in);
		  char s1= s.next().charAt(0);
		  
		  if(s1 >='A' && s1 <= 'Z')
		    System.out.println("A");
		   else
		  	System.out.println("a");
	}

} Main public static void main(String[] args) {
			Scanner s= new Scanner(System.in);
		  char s1= s.next().charAt(0);
		  
		  if(s1 >='A' && s1 <= 'Z')
		    System.out.println("A");
		   else
		  	System.out.println("a");
	} main {
			Scanner s= new Scanner(System.in);
		  char s1= s.next().charAt(0);
		  
		  if(s1 >='A' && s1 <= 'Z')
		    System.out.println("A");
		   else
		  	System.out.println("a");
	} Scanner s= new Scanner(System.in); s new Scanner(System.in) char s1= s.next().charAt(0); s1 s.next().charAt(0) s.next().charAt s.next() s.next s 0 if(s1 >='A' && s1 <= 'Z')
		    System.out.println("A");
		   else
		  	System.out.println("a"); s1 >='A' && s1 <= 'Z' s1 >='A' s1 'A' s1 <= 'Z' s1 'Z' 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 s= new Scanner(System.in);
		  char s1= s.next().charAt(0);
		  
		  if(s1 >='A' && s1 <= 'Z')
		    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 s1= s.next().charAt(0);
		  
		  if(s1 >='A' && s1 <= 'Z')
		    System.out.println("A");
		   else
		  	System.out.println("a");
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
			Scanner s= new Scanner(System.in);
		  char s1= s.next().charAt(0);
		  
		  if(s1 >='A' && s1 <= 'Z')
		    System.out.println("A");
		   else
		  	System.out.println("a");
	}

}
