import java.util.Scanner;


public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		String s = scan.next();
		
		if(!s.equals(s.toLowerCase()))
			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 scan = new Scanner(System.in);
		
		String s = scan.next();
		
		if(!s.equals(s.toLowerCase()))
			System.out.println("A");
		else
			System.out.println("a");
				
		

	}

} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		String s = scan.next();
		
		if(!s.equals(s.toLowerCase()))
			System.out.println("A");
		else
			System.out.println("a");
				
		

	} main {
		Scanner scan = new Scanner(System.in);
		
		String s = scan.next();
		
		if(!s.equals(s.toLowerCase()))
			System.out.println("A");
		else
			System.out.println("a");
				
		

	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) String s = scan.next(); s scan.next() scan.next scan if(!s.equals(s.toLowerCase()))
			System.out.println("A");
		else
			System.out.println("a"); !s.equals(s.toLowerCase()) s.equals(s.toLowerCase()) s.equals s s.toLowerCase() s.toLowerCase s 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 scan = new Scanner(System.in);
		
		String s = scan.next();
		
		if(!s.equals(s.toLowerCase()))
			System.out.println("A");
		else
			System.out.println("a");
				
		

	}

} public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		String s = scan.next();
		
		if(!s.equals(s.toLowerCase()))
			System.out.println("A");
		else
			System.out.println("a");
				
		

	}

} Main
import java.util.Scanner;


public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		String s = scan.next();
		
		if(!s.equals(s.toLowerCase()))
			System.out.println("A");
		else
			System.out.println("a");
				
		

	}

}
