import java.util.*;

public class Main {

    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        System.out.print("");
        String str = scanner.nextLine();

        if(Character.isUpperCase(str.charAt(0))){
            System.out.println("A");
        }else{
            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