import java.util.Scanner;
class Main{
	public static void main(String[] args){
    	Scanner sc = new Scanner(System.in);
      	String s = sc.next();
      	switch(s){
          case "A":
          case "B":
          case "C":
          case "D":
          case "E":
          case "F":
          case "G":
          case "H":
          case "I":
          case "J":
          case "K":
          case "L":
          case "M":
          case "N":
          case "O":
          case "P":
          case "Q":
          case "R":
          case "S":
          case "T":
          case "U":
          case "V":
          case "W":
          case "X":
          case "Y":
          case "Z":
            System.out.println("A");
            break;}
      	switch(s){
          case "a":
          case "b":
          case "c":
          case "d":
          case "e":
          case "f":
          case "g":
          case "h":
          case "i":
          case "j":
          case "k":
          case "l":
          case "m":
          case "n":
          case "o":
          case "p":
          case "q":
          case "r":
          case "s":
          case "t":
          case "u":
          case "v":
          case "w":
          case "x":
          case "y":
          case "z":
            System.out.println("a");
        
              
            
              
        }
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz