import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char c;
		String str;
		str = sc.next();
		c = str.charAt(0);
		if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		}
		
		sc.close();

	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char c;
		String str;
		str = sc.next();
		c = str.charAt(0);
		if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		}
		
		sc.close();

	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char c;
		String str;
		str = sc.next();
		c = str.charAt(0);
		if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		}
		
		sc.close();

	} main {
		Scanner sc = new Scanner(System.in);
		char c;
		String str;
		str = sc.next();
		c = str.charAt(0);
		if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		}
		
		sc.close();

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char c; c String str; str str = sc.next() str sc.next() sc.next sc c = str.charAt(0) c str.charAt(0) str.charAt str 0 if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		} (c >= 'a')&&(c <= 'z') (c >= 'a') c 'a' (c <= 'z') c 'z' {
			System.out.println("a");
		} System.out.println("a") System.out.println System.out System System.out "a" if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		} (c >= 'A')&&(c <= 'Z') (c >= 'A') c 'A' (c <= 'Z') c 'Z' {
			System.out.println("A");
		} System.out.println("A") System.out.println System.out System System.out "A" sc.close() sc.close sc String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char c;
		String str;
		str = sc.next();
		c = str.charAt(0);
		if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		}
		
		sc.close();

	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char c;
		String str;
		str = sc.next();
		c = str.charAt(0);
		if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		}
		
		sc.close();

	}

} Main
import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		char c;
		String str;
		str = sc.next();
		c = str.charAt(0);
		if((c >= 'a')&&(c <= 'z')){
			System.out.println("a");
		}else if((c >= 'A')&&(c <= 'Z')) {
			System.out.println("A");
		}
		
		sc.close();

	}

}