import  java.io.InputStreamReader;
import  java.io.BufferedReader;
import java.io.IOException;

class Main {
	public static void main(String[] args){
	char s;
    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
	String str = null;
    try {
            str = br.readLine();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
      
      if(str.compareTo("a") < 0){
      	System.out.println("A");
      }
      else{
		System.out.println("a");
      }
        
    }
} import  java.io.InputStreamReader; InputStreamReader java.io import  java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io class Main {
	public static void main(String[] args){
	char s;
    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
	String str = null;
    try {
            str = br.readLine();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
      
      if(str.compareTo("a") < 0){
      	System.out.println("A");
      }
      else{
		System.out.println("a");
      }
        
    }
} Main public static void main(String[] args){
	char s;
    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
	String str = null;
    try {
            str = br.readLine();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
      
      if(str.compareTo("a") < 0){
      	System.out.println("A");
      }
      else{
		System.out.println("a");
      }
        
    } main {
	char s;
    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
	String str = null;
    try {
            str = br.readLine();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
      
      if(str.compareTo("a") < 0){
      	System.out.println("A");
      }
      else{
		System.out.println("a");
      }
        
    } char s; s InputStreamReader isr = new InputStreamReader(System.in); isr new InputStreamReader(System.in) BufferedReader br = new BufferedReader(isr); br new BufferedReader(isr) String str = null; str null try {
            str = br.readLine();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } IOException e {
            e.printStackTrace();
        } e.printStackTrace() e.printStackTrace e {
            str = br.readLine();
            br.close();
        } str = br.readLine() str br.readLine() br.readLine br br.close() br.close br if(str.compareTo("a") < 0){
      	System.out.println("A");
      }
      else{
		System.out.println("a");
      } str.compareTo("a") < 0 str.compareTo("a") str.compareTo str "a" 0 {
      	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
import  java.io.InputStreamReader;
import  java.io.BufferedReader;
import java.io.IOException;

class Main {
	public static void main(String[] args){
	char s;
    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);
	String str = null;
    try {
            str = br.readLine();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
      
      if(str.compareTo("a") < 0){
      	System.out.println("A");
      }
      else{
		System.out.println("a");
      }
        
    }
}