import java.util.*;

class Main {
  public static void main(String[] args) {
  Scanner sc = new Scanner(System.in);
  char ch = sc.next().charAt(0);
  int asciival = ch -'A';
  if(0 <= asciival && asciival <= 26)
    System.out.println("A");
  else
    System.out.println("a");
  }
} import java.util.*; util.* java class Main {
  public static void main(String[] args) {
  Scanner sc = new Scanner(System.in);
  char ch = sc.next().charAt(0);
  int asciival = ch -'A';
  if(0 <= asciival && asciival <= 26)
    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);
  int asciival = ch -'A';
  if(0 <= asciival && asciival <= 26)
    System.out.println("A");
  else
    System.out.println("a");
  } main {
  Scanner sc = new Scanner(System.in);
  char ch = sc.next().charAt(0);
  int asciival = ch -'A';
  if(0 <= asciival && asciival <= 26)
    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 int asciival = ch -'A'; asciival ch -'A' ch 'A' if(0 <= asciival && asciival <= 26)
    System.out.println("A");
  else
    System.out.println("a"); 0 <= asciival && asciival <= 26 0 <= asciival 0 asciival asciival <= 26 asciival 26 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
import java.util.*;

class Main {
  public static void main(String[] args) {
  Scanner sc = new Scanner(System.in);
  char ch = sc.next().charAt(0);
  int asciival = ch -'A';
  if(0 <= asciival && asciival <= 26)
    System.out.println("A");
  else
    System.out.println("a");
  }
}
