import java.io.*;
// import java.math.*;
// import java.util.*;
// import java.util.Map.*;
// import java.util.stream.*;

public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        char a = reader.readLine().charAt (0);
        System.out.println (a <= 'Z' ? "A" : "a");
        return;
    }
} import java.io.*; io.* java public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        char a = reader.readLine().charAt (0);
        System.out.println (a <= 'Z' ? "A" : "a");
        return;
    }
} Main public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        char a = reader.readLine().charAt (0);
        System.out.println (a <= 'Z' ? "A" : "a");
        return;
    } main {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        char a = reader.readLine().charAt (0);
        System.out.println (a <= 'Z' ? "A" : "a");
        return;
    } BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in)); reader new BufferedReader (new InputStreamReader (System.in)) char a = reader.readLine().charAt (0); a reader.readLine().charAt (0) reader.readLine().charAt reader.readLine() reader.readLine reader 0 System.out.println (a <= 'Z' ? "A" : "a") System.out.println System.out System System.out a <= 'Z' ? "A" : "a" a <= 'Z' a 'Z' "A" "a" return; String[] args args public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        char a = reader.readLine().charAt (0);
        System.out.println (a <= 'Z' ? "A" : "a");
        return;
    }
} public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        char a = reader.readLine().charAt (0);
        System.out.println (a <= 'Z' ? "A" : "a");
        return;
    }
} Main
import java.io.*;
// import java.math.*;
// import java.util.*;
// import java.util.Map.*;
// import java.util.stream.*;

public class Main {
    public static void main (String[] args) throws Exception {
        BufferedReader reader =
            new BufferedReader (new InputStreamReader (System.in));
        char a = reader.readLine().charAt (0);
        System.out.println (a <= 'Z' ? "A" : "a");
        return;
    }
}