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