    import java.util.Scanner;
     
    public class Main {
     
        public static void main(String[] args) {
            @SuppressWarnings("resource")
            Scanner sc = new Scanner(System.in);
            char c = sc.next().toCharArray()[0];
            System.out.println(c >= 'a' ? '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