import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
        char[] s = sc.next().toCharArray();
    
        String res;
        if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        }
        System.out.println(res);
        }
    } import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
        char[] s = sc.next().toCharArray();
    
        String res;
        if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        }
        System.out.println(res);
        }
    } Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
        char[] s = sc.next().toCharArray();
    
        String res;
        if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        }
        System.out.println(res);
        } main {
		Scanner sc = new Scanner(System.in);
        char[] s = sc.next().toCharArray();
    
        String res;
        if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        }
        System.out.println(res);
        } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char[] s = sc.next().toCharArray(); s sc.next().toCharArray() sc.next().toCharArray sc.next() sc.next sc String res; res if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        } 'A' <= s[0] && s[0] <='Z' 'A' <= s[0] 'A' s[0] s 0 s[0] <='Z' s[0] s 0 'Z' {
            res = "A";
        } res = "A" res "A" {
            res ="a";
        } res ="a" res "a" System.out.println(res) System.out.println System.out System System.out res String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
        char[] s = sc.next().toCharArray();
    
        String res;
        if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        }
        System.out.println(res);
        }
    } public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
        char[] s = sc.next().toCharArray();
    
        String res;
        if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        }
        System.out.println(res);
        }
    } Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
        char[] s = sc.next().toCharArray();
    
        String res;
        if('A' <= s[0] && s[0] <='Z'){
            res = "A";
        }else{
            res ="a";
        }
        System.out.println(res);
        }
    }