import java.util.*;
public class Main{
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String s = sc.next();
    char c = s.charAt(0);

    if('a' <= c && c <= 'z'){
      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 s = sc.next();
    char c = s.charAt(0);

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

    if('a' <= c && c <= 'z'){
      System.out.println("a");
    }else{
      System.out.println("A");
    }
  } main {
    Scanner sc = new Scanner(System.in);
    String s = sc.next();
    char c = s.charAt(0);

    if('a' <= c && c <= 'z'){
      System.out.println("a");
    }else{
      System.out.println("A");
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.next(); s sc.next() sc.next sc char c = s.charAt(0); c s.charAt(0) s.charAt s 0 if('a' <= c && c <= 'z'){
      System.out.println("a");
    }else{
      System.out.println("A");
    } 'a' <= c && c <= 'z' 'a' <= c 'a' c c <= 'z' c 'z' {
      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 s = sc.next();
    char c = s.charAt(0);

    if('a' <= c && c <= 'z'){
      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 s = sc.next();
    char c = s.charAt(0);

    if('a' <= c && c <= 'z'){
      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 s = sc.next();
    char c = s.charAt(0);

    if('a' <= c && c <= 'z'){
      System.out.println("a");
    }else{
      System.out.println("A");
    }
  }
}
