import java.lang.reflect.Array;
import java.math.BigInteger;
import java.nio.Buffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
import java.util.Vector;

public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        String ch=r.next();
        char c=ch.charAt(0);
        if(c>='a'&&c<='z') System.out.println('a');
        else System.out.println('A');
    }
} import java.lang.reflect.Array; Array java.lang.reflect import java.math.BigInteger; BigInteger java.math import java.nio.Buffer; Buffer java.nio import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.Scanner; Scanner java.util import java.util.Vector; Vector java.util public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        String ch=r.next();
        char c=ch.charAt(0);
        if(c>='a'&&c<='z') System.out.println('a');
        else System.out.println('A');
    }
} Main public static Scanner r=new Scanner(System.in); r new Scanner(System.in) public static void main(String[] args) {
        String ch=r.next();
        char c=ch.charAt(0);
        if(c>='a'&&c<='z') System.out.println('a');
        else System.out.println('A');
    } main {
        String ch=r.next();
        char c=ch.charAt(0);
        if(c>='a'&&c<='z') System.out.println('a');
        else System.out.println('A');
    } String ch=r.next(); ch r.next() r.next r char c=ch.charAt(0); c ch.charAt(0) ch.charAt ch 0 if(c>='a'&&c<='z') System.out.println('a');
        else System.out.println('A'); c>='a'&&c<='z' c>='a' c 'a' c<='z' c '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 public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        String ch=r.next();
        char c=ch.charAt(0);
        if(c>='a'&&c<='z') System.out.println('a');
        else System.out.println('A');
    }
} public class Main {
    public static Scanner r=new Scanner(System.in);
    public static void main(String[] args) {
        String ch=r.next();
        char c=ch.charAt(0);
        if(c>='a'&&c<='z') System.out.println('a');
        else System.out.println('A');
    }
} Main
import java.lang.reflect.Array;
import java.math.BigInteger;
import java.nio.Buffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
import java.util.Vector;

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