import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String a = scan.nextLine();
		if (a.matches("[a-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 scan = new Scanner(System.in);
		String a = scan.nextLine();
		if (a.matches("[a-z]")) {
			System.out.println("a");
		}else {
			System.out.println("A");
		}
	}

} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String a = scan.nextLine();
		if (a.matches("[a-z]")) {
			System.out.println("a");
		}else {
			System.out.println("A");
		}
	} main {
		Scanner scan = new Scanner(System.in);
		String a = scan.nextLine();
		if (a.matches("[a-z]")) {
			System.out.println("a");
		}else {
			System.out.println("A");
		}
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) String a = scan.nextLine(); a scan.nextLine() scan.nextLine scan if (a.matches("[a-z]")) {
			System.out.println("a");
		}else {
			System.out.println("A");
		} a.matches("[a-z]") a.matches a "[a-z]" {
			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 scan = new Scanner(System.in);
		String a = scan.nextLine();
		if (a.matches("[a-z]")) {
			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 a = scan.nextLine();
		if (a.matches("[a-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 scan = new Scanner(System.in);
		String a = scan.nextLine();
		if (a.matches("[a-z]")) {
			System.out.println("a");
		}else {
			System.out.println("A");
		}
	}

}
