import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        boolean lowercase = !s.equals(s.toLowerCase());
        boolean uppercase = !s.equals(s.toUpperCase());
        if (!lowercase) {
            System.out.println("a");
        }
        if (!uppercase) {
            System.out.println("A");
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        boolean lowercase = !s.equals(s.toLowerCase());
        boolean uppercase = !s.equals(s.toUpperCase());
        if (!lowercase) {
            System.out.println("a");
        }
        if (!uppercase) {
            System.out.println("A");
        }
    }
} Main public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        boolean lowercase = !s.equals(s.toLowerCase());
        boolean uppercase = !s.equals(s.toUpperCase());
        if (!lowercase) {
            System.out.println("a");
        }
        if (!uppercase) {
            System.out.println("A");
        }
    } main {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        boolean lowercase = !s.equals(s.toLowerCase());
        boolean uppercase = !s.equals(s.toUpperCase());
        if (!lowercase) {
            System.out.println("a");
        }
        if (!uppercase) {
            System.out.println("A");
        }
    } Scanner in = new Scanner(System.in); in new Scanner(System.in) String s = in.next(); s in.next() in.next in boolean lowercase = !s.equals(s.toLowerCase()); lowercase !s.equals(s.toLowerCase()) s.equals(s.toLowerCase()) s.equals s s.toLowerCase() s.toLowerCase s boolean uppercase = !s.equals(s.toUpperCase()); uppercase !s.equals(s.toUpperCase()) s.equals(s.toUpperCase()) s.equals s s.toUpperCase() s.toUpperCase s if (!lowercase) {
            System.out.println("a");
        } !lowercase lowercase {
            System.out.println("a");
        } System.out.println("a") System.out.println System.out System System.out "a" if (!uppercase) {
            System.out.println("A");
        } !uppercase uppercase {
            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 in = new Scanner(System.in);
        String s = in.next();
        boolean lowercase = !s.equals(s.toLowerCase());
        boolean uppercase = !s.equals(s.toUpperCase());
        if (!lowercase) {
            System.out.println("a");
        }
        if (!uppercase) {
            System.out.println("A");
        }
    }
} public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        boolean lowercase = !s.equals(s.toLowerCase());
        boolean uppercase = !s.equals(s.toUpperCase());
        if (!lowercase) {
            System.out.println("a");
        }
        if (!uppercase) {
            System.out.println("A");
        }
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.next();
        boolean lowercase = !s.equals(s.toLowerCase());
        boolean uppercase = !s.equals(s.toUpperCase());
        if (!lowercase) {
            System.out.println("a");
        }
        if (!uppercase) {
            System.out.println("A");
        }
    }
}