import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
      	String s = sc.next();
        if( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          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( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          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( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          System.out.println('A');
        }else{
          System.out.println('a');
        }      
	} main {
		Scanner sc = new Scanner(System.in);
      	String s = sc.next();
        if( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          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( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          System.out.println('A');
        }else{
          System.out.println('a');
        } (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 (int)s.charAt(0)-48 >= 0 (int)s.charAt(0)-48 (int)s.charAt(0) s.charAt s 0 48 0 (int)s.charAt(0)-48 <=48 (int)s.charAt(0)-48 (int)s.charAt(0) s.charAt s 0 48 48 {
          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( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          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( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          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( (int)s.charAt(0)-48 >= 0 && (int)s.charAt(0)-48 <=48 ){
          System.out.println('A');
        }else{
          System.out.println('a');
        }      
	}
}