import java.util.*;


public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();
		if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		}
		
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();
		if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		}
		
    }
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();
		if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		}
		
    } main {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();
		if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		}
		
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String line = sc.next(); line sc.next() sc.next sc if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		} line.equals(line.toLowerCase()) line.equals line line.toLowerCase() line.toLowerCase line {
		    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 public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();
		if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		}
		
    }
} public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();
		if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		}
		
    }
} Main
import java.util.*;


public class Main {
    public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();
		if (line.equals(line.toLowerCase())) {
		    System.out.println("a");
		} else {
		    System.out.println("A");
		}
		
    }
}