import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String a = br.readLine();
		String b = a;
		b = a.toUpperCase();
		if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		}
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String a = br.readLine();
		String b = a;
		b = a.toUpperCase();
		if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		}
	}
} Main public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String a = br.readLine();
		String b = a;
		b = a.toUpperCase();
		if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		}
	} main {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String a = br.readLine();
		String b = a;
		b = a.toUpperCase();
		if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		}
	} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) String a = br.readLine(); a br.readLine() br.readLine br String b = a; b a b = a.toUpperCase() b a.toUpperCase() a.toUpperCase a if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		} a == b a b {
			System.out.print("A");
		} System.out.print("A") System.out.print System.out System System.out "A" {
			System.out.print("a");
		} System.out.print("a") System.out.print System.out System System.out "a" String[] args args public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String a = br.readLine();
		String b = a;
		b = a.toUpperCase();
		if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		}
	}
} public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String a = br.readLine();
		String b = a;
		b = a.toUpperCase();
		if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		}
	}
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String a = br.readLine();
		String b = a;
		b = a.toUpperCase();
		if (a == b) {
			System.out.print("A");
		} else {
			System.out.print("a");
		}
	}
}