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