import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {

        Scanner sc = new Scanner(System.in);
        char c = sc.next().toCharArray()[0];
        if('a'<=c && c<='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);
        char c = sc.next().toCharArray()[0];
        if('a'<=c && c<='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);
        char c = sc.next().toCharArray()[0];
        if('a'<=c && c<='z') {
            System.out.println('a');
        } else {
            System.out.println('A');
        }

    } main {

        Scanner sc = new Scanner(System.in);
        char c = sc.next().toCharArray()[0];
        if('a'<=c && c<='z') {
            System.out.println('a');
        } else {
            System.out.println('A');
        }

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char c = sc.next().toCharArray()[0]; c sc.next().toCharArray()[0] sc.next().toCharArray() sc.next().toCharArray sc.next() sc.next sc 0 if('a'<=c && c<='z') {
            System.out.println('a');
        } else {
            System.out.println('A');
        } 'a'<=c && c<='z' 'a'<=c 'a' c c<='z' c '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);
        char c = sc.next().toCharArray()[0];
        if('a'<=c && c<='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);
        char c = sc.next().toCharArray()[0];
        if('a'<=c && c<='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);
        char c = sc.next().toCharArray()[0];
        if('a'<=c && c<='z') {
            System.out.println('a');
        } else {
            System.out.println('A');
        }

    }

}