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