import java.util.*;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        char letter = sc.next().charAt(0);

        if(letter>='A' && letter <= 'Z'){
            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 letter = sc.next().charAt(0);

        if(letter>='A' && letter <= 'Z'){
            System.out.println("A");
        }
        else{
            System.out.println("a");
        }



    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        char letter = sc.next().charAt(0);

        if(letter>='A' && letter <= 'Z'){
            System.out.println("A");
        }
        else{
            System.out.println("a");
        }



    } main {
        Scanner sc = new Scanner(System.in);
        char letter = sc.next().charAt(0);

        if(letter>='A' && letter <= 'Z'){
            System.out.println("A");
        }
        else{
            System.out.println("a");
        }



    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char letter = sc.next().charAt(0); letter sc.next().charAt(0) sc.next().charAt sc.next() sc.next sc 0 if(letter>='A' && letter <= 'Z'){
            System.out.println("A");
        }
        else{
            System.out.println("a");
        } letter>='A' && letter <= 'Z' letter>='A' letter 'A' letter <= 'Z' letter 'Z' {
            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);
        char letter = sc.next().charAt(0);

        if(letter>='A' && letter <= 'Z'){
            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 letter = sc.next().charAt(0);

        if(letter>='A' && letter <= 'Z'){
            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 letter = sc.next().charAt(0);

        if(letter>='A' && letter <= 'Z'){
            System.out.println("A");
        }
        else{
            System.out.println("a");
        }



    }
}