import java.util.*;
public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		char s=sc.next().charAt(0);
		if(Character.isUpperCase(s)){
		 System.out.println("A");   
		}
		if(Character.isLowerCase(s)){
		 System.out.println("a");     
		}
	}
} import java.util.*; util.* java public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		char s=sc.next().charAt(0);
		if(Character.isUpperCase(s)){
		 System.out.println("A");   
		}
		if(Character.isLowerCase(s)){
		 System.out.println("a");     
		}
	}
} Main public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		char s=sc.next().charAt(0);
		if(Character.isUpperCase(s)){
		 System.out.println("A");   
		}
		if(Character.isLowerCase(s)){
		 System.out.println("a");     
		}
	} main {
		Scanner sc=new Scanner(System.in);
		char s=sc.next().charAt(0);
		if(Character.isUpperCase(s)){
		 System.out.println("A");   
		}
		if(Character.isLowerCase(s)){
		 System.out.println("a");     
		}
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) char s=sc.next().charAt(0); s sc.next().charAt(0) sc.next().charAt sc.next() sc.next sc 0 if(Character.isUpperCase(s)){
		 System.out.println("A");   
		} Character.isUpperCase(s) Character.isUpperCase Character s {
		 System.out.println("A");   
		} System.out.println("A") System.out.println System.out System System.out "A" if(Character.isLowerCase(s)){
		 System.out.println("a");     
		} Character.isLowerCase(s) Character.isLowerCase Character s {
		 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);
		char s=sc.next().charAt(0);
		if(Character.isUpperCase(s)){
		 System.out.println("A");   
		}
		if(Character.isLowerCase(s)){
		 System.out.println("a");     
		}
	}
} public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		char s=sc.next().charAt(0);
		if(Character.isUpperCase(s)){
		 System.out.println("A");   
		}
		if(Character.isLowerCase(s)){
		 System.out.println("a");     
		}
	}
} Main
import java.util.*;
public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		char s=sc.next().charAt(0);
		if(Character.isUpperCase(s)){
		 System.out.println("A");   
		}
		if(Character.isLowerCase(s)){
		 System.out.println("a");     
		}
	}
}