import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		}
		stdIn.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		}
		stdIn.close();
	}
} Main public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		}
		stdIn.close();
	} main {
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		}
		stdIn.close();
	} Scanner stdIn = new Scanner(System.in); stdIn new Scanner(System.in) String A = stdIn.next(); A stdIn.next() stdIn.next stdIn if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		} A == A.toLowerCase() A A.toLowerCase() A.toLowerCase A {
			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" stdIn.close() stdIn.close stdIn String[] args args public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		}
		stdIn.close();
	}
} public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		}
		stdIn.close();
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		if(A == A.toLowerCase()){
			System.out.println("a");
		}
		else{
			System.out.println("A");
		}
		stdIn.close();
	}
}