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