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

class Main {
	public static void main (String[] args) {
	    Scanner sc = new Scanner(System.in);
	    char ch = sc.next().charAt(0);
	    if(Character.isUpperCase(ch)){
	        System.out.println("A");
	    } else{
	        System.out.println("a");
	    }
	}
} import java.io.*; io.* java import java.util.*; util.* java import java.lang.*; lang.* java class Main {
	public static void main (String[] args) {
	    Scanner sc = new Scanner(System.in);
	    char ch = sc.next().charAt(0);
	    if(Character.isUpperCase(ch)){
	        System.out.println("A");
	    } else{
	        System.out.println("a");
	    }
	}
} Main public static void main (String[] args) {
	    Scanner sc = new Scanner(System.in);
	    char ch = sc.next().charAt(0);
	    if(Character.isUpperCase(ch)){
	        System.out.println("A");
	    } else{
	        System.out.println("a");
	    }
	} main {
	    Scanner sc = new Scanner(System.in);
	    char ch = sc.next().charAt(0);
	    if(Character.isUpperCase(ch)){
	        System.out.println("A");
	    } else{
	        System.out.println("a");
	    }
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char ch = sc.next().charAt(0); ch sc.next().charAt(0) sc.next().charAt sc.next() sc.next sc 0 if(Character.isUpperCase(ch)){
	        System.out.println("A");
	    } else{
	        System.out.println("a");
	    } Character.isUpperCase(ch) Character.isUpperCase Character ch {
	        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
import java.io.*;
import java.util.*;
import java.lang.*;

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