
import java.util.*;
import java.lang.*;
import java.io.*;

class Main {
    private static BufferedReader br;
	public static void main (String[] args) throws java.lang.Exception
	{
		br=  new BufferedReader(new InputStreamReader(System.in));
		char alpha = br.readLine().charAt(0);
		if(alpha >= 'a' && alpha <= 'z')
		    System.out.println("a");
		else
		    System.out.println("A");
	}
} import java.util.*; util.* java import java.lang.*; lang.* java import java.io.*; io.* java class Main {
    private static BufferedReader br;
	public static void main (String[] args) throws java.lang.Exception
	{
		br=  new BufferedReader(new InputStreamReader(System.in));
		char alpha = br.readLine().charAt(0);
		if(alpha >= 'a' && alpha <= 'z')
		    System.out.println("a");
		else
		    System.out.println("A");
	}
} Main private static BufferedReader br; br public static void main (String[] args) throws java.lang.Exception
	{
		br=  new BufferedReader(new InputStreamReader(System.in));
		char alpha = br.readLine().charAt(0);
		if(alpha >= 'a' && alpha <= 'z')
		    System.out.println("a");
		else
		    System.out.println("A");
	} main {
		br=  new BufferedReader(new InputStreamReader(System.in));
		char alpha = br.readLine().charAt(0);
		if(alpha >= 'a' && alpha <= 'z')
		    System.out.println("a");
		else
		    System.out.println("A");
	} br=  new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) char alpha = br.readLine().charAt(0); alpha br.readLine().charAt(0) br.readLine().charAt br.readLine() br.readLine br 0 if(alpha >= 'a' && alpha <= 'z')
		    System.out.println("a");
		else
		    System.out.println("A"); alpha >= 'a' && alpha <= 'z' alpha >= 'a' alpha 'a' alpha <= 'z' alpha 'z' 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

import java.util.*;
import java.lang.*;
import java.io.*;

class Main {
    private static BufferedReader br;
	public static void main (String[] args) throws java.lang.Exception
	{
		br=  new BufferedReader(new InputStreamReader(System.in));
		char alpha = br.readLine().charAt(0);
		if(alpha >= 'a' && alpha <= 'z')
		    System.out.println("a");
		else
		    System.out.println("A");
	}
}
