import java.util.*;

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

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