import java.util.Scanner;
import java.util.regex.Pattern;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String c = sc.next();
		
		System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a");
	}
} import java.util.Scanner; Scanner java.util import java.util.regex.Pattern; Pattern java.util.regex public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String c = sc.next();
		
		System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a");
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String c = sc.next();
		
		System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a");
	} main {
		Scanner sc = new Scanner(System.in);
		String c = sc.next();
		
		System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String c = sc.next(); c sc.next() sc.next sc System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a") System.out.println System.out System System.out Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a" Pattern.compile("[A-Z]").matcher(c).matches() Pattern.compile("[A-Z]").matcher(c).matches Pattern.compile("[A-Z]").matcher(c) Pattern.compile("[A-Z]").matcher Pattern.compile("[A-Z]") Pattern.compile Pattern "[A-Z]" c "A" "a" String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String c = sc.next();
		
		System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a");
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String c = sc.next();
		
		System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a");
	}
} Main
import java.util.Scanner;
import java.util.regex.Pattern;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String c = sc.next();
		
		System.out.println(Pattern.compile("[A-Z]").matcher(c).matches() ? "A":"a");
	}
}
