import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.matches("[A-Z]")){
            System.out.println("A");
        }else{
            System.out.println("a");
        }
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.matches("[A-Z]")){
            System.out.println("A");
        }else{
            System.out.println("a");
        }
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.matches("[A-Z]")){
            System.out.println("A");
        }else{
            System.out.println("a");
        }
    } main {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.matches("[A-Z]")){
            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(s.matches("[A-Z]")){
            System.out.println("A");
        }else{
            System.out.println("a");
        } s.matches("[A-Z]") s.matches s "[A-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) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.matches("[A-Z]")){
            System.out.println("A");
        }else{
            System.out.println("a");
        }
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.matches("[A-Z]")){
            System.out.println("A");
        }else{
            System.out.println("a");
        }
    }
} Main
import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        if(s.matches("[A-Z]")){
            System.out.println("A");
        }else{
            System.out.println("a");
        }
    }
}