import java.util.*;
import java.io.*;
class Main{
	public static void main(String[] args) {
	Scanner sc=new Scanner(System.in);
	String str= sc.nextLine();
	String str1=str.toUpperCase();
	if(str==str1)
	{
		System.out.println("A");
	}
	else
	{
		System.out.println("a");

	}
	
	
	
				
		
	}
} import java.util.*; util.* java import java.io.*; io.* java class Main{
	public static void main(String[] args) {
	Scanner sc=new Scanner(System.in);
	String str= sc.nextLine();
	String str1=str.toUpperCase();
	if(str==str1)
	{
		System.out.println("A");
	}
	else
	{
		System.out.println("a");

	}
	
	
	
				
		
	}
} Main public static void main(String[] args) {
	Scanner sc=new Scanner(System.in);
	String str= sc.nextLine();
	String str1=str.toUpperCase();
	if(str==str1)
	{
		System.out.println("A");
	}
	else
	{
		System.out.println("a");

	}
	
	
	
				
		
	} main {
	Scanner sc=new Scanner(System.in);
	String str= sc.nextLine();
	String str1=str.toUpperCase();
	if(str==str1)
	{
		System.out.println("A");
	}
	else
	{
		System.out.println("a");

	}
	
	
	
				
		
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) String str= sc.nextLine(); str sc.nextLine() sc.nextLine sc String str1=str.toUpperCase(); str1 str.toUpperCase() str.toUpperCase str if(str==str1)
	{
		System.out.println("A");
	}
	else
	{
		System.out.println("a");

	} str==str1 str str1 {
		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
import java.util.*;
import java.io.*;
class Main{
	public static void main(String[] args) {
	Scanner sc=new Scanner(System.in);
	String str= sc.nextLine();
	String str1=str.toUpperCase();
	if(str==str1)
	{
		System.out.println("A");
	}
	else
	{
		System.out.println("a");

	}
	
	
	
				
		
	}
}