import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		char c[] = A.toCharArray();
		if(c[0]>=0x41 && 0x5a >= c[0]) {
			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();
		char c[] = A.toCharArray();
		if(c[0]>=0x41 && 0x5a >= c[0]) {
			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();
		char c[] = A.toCharArray();
		if(c[0]>=0x41 && 0x5a >= c[0]) {
			System.out.println("A");
		}else {
			System.out.println("a");
		}
		stdIn.close();
	} main {
		Scanner stdIn = new Scanner(System.in);
		String A = stdIn.next();
		char c[] = A.toCharArray();
		if(c[0]>=0x41 && 0x5a >= c[0]) {
			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 char c[] = A.toCharArray(); c A.toCharArray() A.toCharArray A if(c[0]>=0x41 && 0x5a >= c[0]) {
			System.out.println("A");
		}else {
			System.out.println("a");
		} c[0]>=0x41 && 0x5a >= c[0] c[0]>=0x41 c[0] c 0 0x41 0x5a >= c[0] 0x5a c[0] c 0 {
			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();
		char c[] = A.toCharArray();
		if(c[0]>=0x41 && 0x5a >= c[0]) {
			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();
		char c[] = A.toCharArray();
		if(c[0]>=0x41 && 0x5a >= c[0]) {
			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();
		char c[] = A.toCharArray();
		if(c[0]>=0x41 && 0x5a >= c[0]) {
			System.out.println("A");
		}else {
			System.out.println("a");
		}
		stdIn.close();
	}
}
