

import java.util.Scanner;

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

		String a = sc.next();

		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 sc = new Scanner(System.in);

		String a = sc.next();

		if (a.matches("[a-z]"))
			System.out.println("a");
		else
			System.out.println("A");
	}

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

		String a = sc.next();

		if (a.matches("[a-z]"))
			System.out.println("a");
		else
			System.out.println("A");
	} main {
		Scanner sc = new Scanner(System.in);

		String a = sc.next();

		if (a.matches("[a-z]"))
			System.out.println("a");
		else
			System.out.println("A");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String a = sc.next(); a sc.next() sc.next sc 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 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 a = sc.next();

		if (a.matches("[a-z]"))
			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 a = sc.next();

		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 sc = new Scanner(System.in);

		String a = sc.next();

		if (a.matches("[a-z]"))
			System.out.println("a");
		else
			System.out.println("A");
	}

}
