import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String a = sc.nextLine();
		String b = a.toLowerCase();
		if(a.equals(b)){
			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){
		Scanner sc = new Scanner(System.in);
		String a = sc.nextLine();
		String b = a.toLowerCase();
		if(a.equals(b)){
			System.out.println('a');
		}else{
			System.out.println('A');
		}
	}

} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String a = sc.nextLine();
		String b = a.toLowerCase();
		if(a.equals(b)){
			System.out.println('a');
		}else{
			System.out.println('A');
		}
	} main {
		Scanner sc = new Scanner(System.in);
		String a = sc.nextLine();
		String b = a.toLowerCase();
		if(a.equals(b)){
			System.out.println('a');
		}else{
			System.out.println('A');
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String a = sc.nextLine(); a sc.nextLine() sc.nextLine sc String b = a.toLowerCase(); b a.toLowerCase() a.toLowerCase a if(a.equals(b)){
			System.out.println('a');
		}else{
			System.out.println('A');
		} a.equals(b) a.equals a b {
			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 a = sc.nextLine();
		String b = a.toLowerCase();
		if(a.equals(b)){
			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 a = sc.nextLine();
		String b = a.toLowerCase();
		if(a.equals(b)){
			System.out.println('a');
		}else{
			System.out.println('A');
		}
	}

} Main
import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String a = sc.nextLine();
		String b = a.toLowerCase();
		if(a.equals(b)){
			System.out.println('a');
		}else{
			System.out.println('A');
		}
	}

}