import java.io.IOException;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws IOException {
    	Scanner sc = new Scanner(System.in);

		char Alpa = sc.next().charAt(0);
		
		if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a');

	}

} import java.io.IOException; IOException java.io import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) throws IOException {
    	Scanner sc = new Scanner(System.in);

		char Alpa = sc.next().charAt(0);
		
		if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a');

	}

} Main public static void main(String[] args) throws IOException {
    	Scanner sc = new Scanner(System.in);

		char Alpa = sc.next().charAt(0);
		
		if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a');

	} main {
    	Scanner sc = new Scanner(System.in);

		char Alpa = sc.next().charAt(0);
		
		if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a');

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char Alpa = sc.next().charAt(0); Alpa sc.next().charAt(0) sc.next().charAt sc.next() sc.next sc 0 if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a'); Character.isUpperCase(Alpa) Character.isUpperCase Character Alpa 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) throws IOException {
    	Scanner sc = new Scanner(System.in);

		char Alpa = sc.next().charAt(0);
		
		if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a');

	}

} public class Main {
	public static void main(String[] args) throws IOException {
    	Scanner sc = new Scanner(System.in);

		char Alpa = sc.next().charAt(0);
		
		if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a');

	}

} Main
import java.io.IOException;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws IOException {
    	Scanner sc = new Scanner(System.in);

		char Alpa = sc.next().charAt(0);
		
		if(Character.isUpperCase(Alpa))
			System.out.println('A');
		else
			System.out.println('a');

	}

}