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