import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.List;

public class Main {

  static int n;
  static long[] ans;
  static List<Long> x, y, p;

  public static void main(String[] args) throws Exception {

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);

    String[] in = br.readLine().split(" ");

    br.close();

    out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A");

    out.flush();
  }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.PrintWriter; PrintWriter java.io import java.util.List; List java.util public class Main {

  static int n;
  static long[] ans;
  static List<Long> x, y, p;

  public static void main(String[] args) throws Exception {

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);

    String[] in = br.readLine().split(" ");

    br.close();

    out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A");

    out.flush();
  }
} Main static int n; n static long[] ans; ans static List<Long> x x y y p; p public static void main(String[] args) throws Exception {

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);

    String[] in = br.readLine().split(" ");

    br.close();

    out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A");

    out.flush();
  } main {

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);

    String[] in = br.readLine().split(" ");

    br.close();

    out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A");

    out.flush();
  } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) String[] in = br.readLine().split(" "); in br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " br.close() br.close br out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A") out.println out in[0].charAt(0) - 'a' >= 0 ? "a" : "A" in[0].charAt(0) - 'a' >= 0 in[0].charAt(0) - 'a' in[0].charAt(0) in[0].charAt in[0] in 0 0 'a' 0 "a" "A" out.flush() out.flush out String[] args args public class Main {

  static int n;
  static long[] ans;
  static List<Long> x, y, p;

  public static void main(String[] args) throws Exception {

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);

    String[] in = br.readLine().split(" ");

    br.close();

    out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A");

    out.flush();
  }
} public class Main {

  static int n;
  static long[] ans;
  static List<Long> x, y, p;

  public static void main(String[] args) throws Exception {

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);

    String[] in = br.readLine().split(" ");

    br.close();

    out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A");

    out.flush();
  }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.List;

public class Main {

  static int n;
  static long[] ans;
  static List<Long> x, y, p;

  public static void main(String[] args) throws Exception {

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter out = new PrintWriter(System.out);

    String[] in = br.readLine().split(" ");

    br.close();

    out.println(in[0].charAt(0) - 'a' >= 0 ? "a" : "A");

    out.flush();
  }
}
