import java.util.Scanner;

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

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