import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char ch = sc.next().trim().charAt(0);
		
		StringBuilder sb = new StringBuilder();
		
		if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n");
		
		sc.close();
		
		System.out.println(sb);
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char ch = sc.next().trim().charAt(0);
		
		StringBuilder sb = new StringBuilder();
		
		if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n");
		
		sc.close();
		
		System.out.println(sb);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char ch = sc.next().trim().charAt(0);
		
		StringBuilder sb = new StringBuilder();
		
		if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n");
		
		sc.close();
		
		System.out.println(sb);
	} main {
		Scanner sc = new Scanner(System.in);
		
		char ch = sc.next().trim().charAt(0);
		
		StringBuilder sb = new StringBuilder();
		
		if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n");
		
		sc.close();
		
		System.out.println(sb);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char ch = sc.next().trim().charAt(0); ch sc.next().trim().charAt(0) sc.next().trim().charAt sc.next().trim() sc.next().trim sc.next() sc.next sc 0 StringBuilder sb = new StringBuilder(); sb new StringBuilder() if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n"); ch >= 'A' && ch <='Z' ch >= 'A' ch 'A' ch <='Z' ch 'Z' sb.append('A' + "\n") sb.append sb 'A' + "\n" 'A' "\n" if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n"); ch >='a' && ch <= 'z' ch >='a' ch 'a' ch <= 'z' ch 'z' sb.append('a' + "\n") sb.append sb 'a' + "\n" 'a' "\n" sc.close() sc.close sc System.out.println(sb) System.out.println System.out System System.out sb String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char ch = sc.next().trim().charAt(0);
		
		StringBuilder sb = new StringBuilder();
		
		if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n");
		
		sc.close();
		
		System.out.println(sb);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char ch = sc.next().trim().charAt(0);
		
		StringBuilder sb = new StringBuilder();
		
		if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n");
		
		sc.close();
		
		System.out.println(sb);
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		char ch = sc.next().trim().charAt(0);
		
		StringBuilder sb = new StringBuilder();
		
		if(ch >= 'A' && ch <='Z')
			sb.append('A' + "\n");
		else if(ch >='a' && ch <= 'z')
			sb.append('a' + "\n");
		
		sc.close();
		
		System.out.println(sb);
	}

}