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