import java.util.*;

public class Main {
    public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
      	String A = sc.next();
        int i = 1;
        if(A.matches("[A-Z]")){
            System.out.println("A");
        } else {
            System.out.println("a");
        }

    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
      	String A = sc.next();
        int i = 1;
        if(A.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 A = sc.next();
        int i = 1;
        if(A.matches("[A-Z]")){
            System.out.println("A");
        } else {
            System.out.println("a");
        }

    } main {
        Scanner sc = new Scanner(System.in);
      	String A = sc.next();
        int i = 1;
        if(A.matches("[A-Z]")){
            System.out.println("A");
        } else {
            System.out.println("a");
        }

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String A = sc.next(); A sc.next() sc.next sc int i = 1; i 1 if(A.matches("[A-Z]")){
            System.out.println("A");
        } else {
            System.out.println("a");
        } A.matches("[A-Z]") A.matches A "[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 A = sc.next();
        int i = 1;
        if(A.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 A = sc.next();
        int i = 1;
        if(A.matches("[A-Z]")){
            System.out.println("A");
        } else {
            System.out.println("a");
        }

    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args ) throws Exception {
        Scanner sc = new Scanner(System.in);
      	String A = sc.next();
        int i = 1;
        if(A.matches("[A-Z]")){
            System.out.println("A");
        } else {
            System.out.println("a");
        }

    }
}
