import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Main {


    public static void main(String[] args) throws IOException {
    
    	Scanner scan = new Scanner(System.in);
   
    	char [] ch = scan.next().toCharArray();
    	
    	if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A");
    	
    
    	
    } 	
} import java.io.*; io.* java import java.math.*; math.* java import java.security.*; security.* java import java.text.*; text.* java import java.util.*; util.* java import java.util.concurrent.*; concurrent.* java.util import java.util.regex.*; regex.* java.util public class Main {


    public static void main(String[] args) throws IOException {
    
    	Scanner scan = new Scanner(System.in);
   
    	char [] ch = scan.next().toCharArray();
    	
    	if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A");
    	
    
    	
    } 	
} Main public static void main(String[] args) throws IOException {
    
    	Scanner scan = new Scanner(System.in);
   
    	char [] ch = scan.next().toCharArray();
    	
    	if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A");
    	
    
    	
    } main {
    
    	Scanner scan = new Scanner(System.in);
   
    	char [] ch = scan.next().toCharArray();
    	
    	if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A");
    	
    
    	
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) char [] ch = scan.next().toCharArray(); ch scan.next().toCharArray() scan.next().toCharArray scan.next() scan.next scan if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A"); Character.isLowerCase(ch[0]) Character.isLowerCase Character ch[0] ch 0 System.out.println("a") System.out.println System.out System System.out "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 IOException {
    
    	Scanner scan = new Scanner(System.in);
   
    	char [] ch = scan.next().toCharArray();
    	
    	if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A");
    	
    
    	
    } 	
} public class Main {


    public static void main(String[] args) throws IOException {
    
    	Scanner scan = new Scanner(System.in);
   
    	char [] ch = scan.next().toCharArray();
    	
    	if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A");
    	
    
    	
    } 	
} Main
import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Main {


    public static void main(String[] args) throws IOException {
    
    	Scanner scan = new Scanner(System.in);
   
    	char [] ch = scan.next().toCharArray();
    	
    	if(Character.isLowerCase(ch[0])) System.out.println("a");
    	else System.out.println("A");
    	
    
    	
    } 	
}
