import java.util.*;class Main{public static void main(String[] a){char c=new Scanner(System.in).next().charAt(0);;System.out.println(Character.isUpperCase(c)?'A':'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