//package beg_171;
import java.util.*;
import java.lang.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		char a = s.nextLine().charAt(0);
		
		boolean b = Character.isUpperCase(a);
		
		if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		}
		
		
	}

} import java.util.*; util.* java import java.lang.*; lang.* java public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		char a = s.nextLine().charAt(0);
		
		boolean b = Character.isUpperCase(a);
		
		if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		}
		
		
	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		char a = s.nextLine().charAt(0);
		
		boolean b = Character.isUpperCase(a);
		
		if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		}
		
		
	} main {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		char a = s.nextLine().charAt(0);
		
		boolean b = Character.isUpperCase(a);
		
		if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		}
		
		
	} Scanner s = new Scanner(System.in); s new Scanner(System.in) char a = s.nextLine().charAt(0); a s.nextLine().charAt(0) s.nextLine().charAt s.nextLine() s.nextLine s 0 boolean b = Character.isUpperCase(a); b Character.isUpperCase(a) Character.isUpperCase Character a if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		} b {
			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 public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		char a = s.nextLine().charAt(0);
		
		boolean b = Character.isUpperCase(a);
		
		if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		}
		
		
	}

} public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		char a = s.nextLine().charAt(0);
		
		boolean b = Character.isUpperCase(a);
		
		if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		}
		
		
	}

} Main
//package beg_171;
import java.util.*;
import java.lang.*;
public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s = new Scanner(System.in);
		char a = s.nextLine().charAt(0);
		
		boolean b = Character.isUpperCase(a);
		
		if (b) {
			System.out.println("A");
		}
		else {
			System.out.println("a");
		}
		
		
	}

}
