import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char a = sc.next().charAt(0);
		
		char ans;
		if (a < 'a')
			ans = 'A';
		else
			ans = 'a';
			
		System.out.println(ans);
	}
}

 import java.util.Scanner; Scanner java.util public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char a = sc.next().charAt(0);
		
		char ans;
		if (a < 'a')
			ans = 'A';
		else
			ans = 'a';
			
		System.out.println(ans);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char a = sc.next().charAt(0);
		
		char ans;
		if (a < 'a')
			ans = 'A';
		else
			ans = 'a';
			
		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		
		char a = sc.next().charAt(0);
		
		char ans;
		if (a < 'a')
			ans = 'A';
		else
			ans = 'a';
			
		System.out.println(ans);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char a = sc.next().charAt(0); a sc.next().charAt(0) sc.next().charAt sc.next() sc.next sc 0 char ans; ans if (a < 'a')
			ans = 'A';
		else
			ans = 'a'; a < 'a' a 'a' ans = 'A' ans 'A' ans = 'a' ans 'a' System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char a = sc.next().charAt(0);
		
		char ans;
		if (a < 'a')
			ans = 'A';
		else
			ans = 'a';
			
		System.out.println(ans);
	}
} public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char a = sc.next().charAt(0);
		
		char ans;
		if (a < 'a')
			ans = 'A';
		else
			ans = 'a';
			
		System.out.println(ans);
	}
} Main
import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char a = sc.next().charAt(0);
		
		char ans;
		if (a < 'a')
			ans = 'A';
		else
			ans = 'a';
			
		System.out.println(ans);
	}
}


