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

public class Main {
    public static void main(String[] args) {
    	Scanner scanner = new Scanner(System.in);
        String a = scanner.next();
        if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        }
        scanner.close();
    }
} 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 scanner = new Scanner(System.in);
        String a = scanner.next();
        if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        }
        scanner.close();
    }
} Main public static void main(String[] args) {
    	Scanner scanner = new Scanner(System.in);
        String a = scanner.next();
        if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        }
        scanner.close();
    } main {
    	Scanner scanner = new Scanner(System.in);
        String a = scanner.next();
        if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        }
        scanner.close();
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String a = scanner.next(); a scanner.next() scanner.next scanner if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        } Pattern.matches("[A-Z]", a) Pattern.matches Pattern "[A-Z]" a {
        	System.out.println("A");
        } System.out.println("A") System.out.println System.out System System.out "A" if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        } Pattern.matches("[a-z]", a) Pattern.matches Pattern "[a-z]" a {
        	System.out.println("a");
        } System.out.println("a") System.out.println System.out System System.out "a" scanner.close() scanner.close scanner String[] args args public class Main {
    public static void main(String[] args) {
    	Scanner scanner = new Scanner(System.in);
        String a = scanner.next();
        if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        }
        scanner.close();
    }
} public class Main {
    public static void main(String[] args) {
    	Scanner scanner = new Scanner(System.in);
        String a = scanner.next();
        if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        }
        scanner.close();
    }
} Main
import java.util.Scanner;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
    	Scanner scanner = new Scanner(System.in);
        String a = scanner.next();
        if(Pattern.matches("[A-Z]", a)) {
        	System.out.println("A");
        }else if(Pattern.matches("[a-z]", a)) {
        	System.out.println("a");
        }
        scanner.close();
    }
}