import java.util.Scanner;

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

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

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

} Main
import java.util.Scanner;

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

}