import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

class Main {

    public static void main(String[] args) {

        Pattern upperCase = Pattern.compile("[A-Z]");
        Pattern lowerCase = Pattern.compile("[a-z]");
        Scanner sc = new Scanner(System.in);
        String input = sc.nextLine();

        Matcher upperMatcher = upperCase.matcher(input);
        Matcher lowerMatcher = lowerCase.matcher(input);

        if(upperMatcher.find()){
            System.out.println("A");
        }else if(lowerMatcher.find()){
            System.out.println("a");
        }
        sc.close();
    }
} import java.util.Scanner; Scanner java.util import java.util.regex.Matcher; Matcher java.util.regex import java.util.regex.Pattern; Pattern java.util.regex class Main {

    public static void main(String[] args) {

        Pattern upperCase = Pattern.compile("[A-Z]");
        Pattern lowerCase = Pattern.compile("[a-z]");
        Scanner sc = new Scanner(System.in);
        String input = sc.nextLine();

        Matcher upperMatcher = upperCase.matcher(input);
        Matcher lowerMatcher = lowerCase.matcher(input);

        if(upperMatcher.find()){
            System.out.println("A");
        }else if(lowerMatcher.find()){
            System.out.println("a");
        }
        sc.close();
    }
} Main public static void main(String[] args) {

        Pattern upperCase = Pattern.compile("[A-Z]");
        Pattern lowerCase = Pattern.compile("[a-z]");
        Scanner sc = new Scanner(System.in);
        String input = sc.nextLine();

        Matcher upperMatcher = upperCase.matcher(input);
        Matcher lowerMatcher = lowerCase.matcher(input);

        if(upperMatcher.find()){
            System.out.println("A");
        }else if(lowerMatcher.find()){
            System.out.println("a");
        }
        sc.close();
    } main {

        Pattern upperCase = Pattern.compile("[A-Z]");
        Pattern lowerCase = Pattern.compile("[a-z]");
        Scanner sc = new Scanner(System.in);
        String input = sc.nextLine();

        Matcher upperMatcher = upperCase.matcher(input);
        Matcher lowerMatcher = lowerCase.matcher(input);

        if(upperMatcher.find()){
            System.out.println("A");
        }else if(lowerMatcher.find()){
            System.out.println("a");
        }
        sc.close();
    } Pattern upperCase = Pattern.compile("[A-Z]"); upperCase Pattern.compile("[A-Z]") Pattern.compile Pattern "[A-Z]" Pattern lowerCase = Pattern.compile("[a-z]"); lowerCase Pattern.compile("[a-z]") Pattern.compile Pattern "[a-z]" Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String input = sc.nextLine(); input sc.nextLine() sc.nextLine sc Matcher upperMatcher = upperCase.matcher(input); upperMatcher upperCase.matcher(input) upperCase.matcher upperCase input Matcher lowerMatcher = lowerCase.matcher(input); lowerMatcher lowerCase.matcher(input) lowerCase.matcher lowerCase input if(upperMatcher.find()){
            System.out.println("A");
        }else if(lowerMatcher.find()){
            System.out.println("a");
        } upperMatcher.find() upperMatcher.find upperMatcher {
            System.out.println("A");
        } System.out.println("A") System.out.println System.out System System.out "A" if(lowerMatcher.find()){
            System.out.println("a");
        } lowerMatcher.find() lowerMatcher.find lowerMatcher {
            System.out.println("a");
        } System.out.println("a") System.out.println System.out System System.out "a" sc.close() sc.close sc String[] args args
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

class Main {

    public static void main(String[] args) {

        Pattern upperCase = Pattern.compile("[A-Z]");
        Pattern lowerCase = Pattern.compile("[a-z]");
        Scanner sc = new Scanner(System.in);
        String input = sc.nextLine();

        Matcher upperMatcher = upperCase.matcher(input);
        Matcher lowerMatcher = lowerCase.matcher(input);

        if(upperMatcher.find()){
            System.out.println("A");
        }else if(lowerMatcher.find()){
            System.out.println("a");
        }
        sc.close();
    }
}
