import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
        String str2 = str.toLowerCase();
        if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");}
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
        String str2 = str.toLowerCase();
        if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");}
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
        String str2 = str.toLowerCase();
        if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");}
	} main {
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
        String str2 = str.toLowerCase();
        if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String str = sc.next(); str sc.next() sc.next sc String str2 = str.toLowerCase(); str2 str.toLowerCase() str.toLowerCase str if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");} str.equals(str2) str.equals str str2 {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 public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
        String str2 = str.toLowerCase();
        if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");}
	}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
        String str2 = str.toLowerCase();
        if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");}
	}
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
        String str2 = str.toLowerCase();
        if(str.equals(str2)){System.out.println("a");}
		else{System.out.println("A");}
	}
}