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

	}

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

	}

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

	} main {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		if(s==s.toUpperCase()) {
			System.out.println("A");
		}else {
			System.out.println("a");
		}

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.next(); s sc.next() sc.next sc if(s==s.toUpperCase()) {
			System.out.println("A");
		}else {
			System.out.println("a");
		} s==s.toUpperCase() s s.toUpperCase() s.toUpperCase s {
			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){
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		if(s==s.toUpperCase()) {
			System.out.println("A");
		}else {
			System.out.println("a");
		}

	}

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

	}

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

	}

}
