import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main
{
    public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }

    static class Task
    {
        public void solve(int testNumber, Scanner in, PrintWriter out)
        {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Scanner; Scanner java.util public class Main
{
    public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }

    static class Task
    {
        public void solve(int testNumber, Scanner in, PrintWriter out)
        {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        }

    }
} Main public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) Task solver = new Task(); solver new Task() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class Task
    {
        public void solve(int testNumber, Scanner in, PrintWriter out)
        {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        }

    } Task public void solve(int testNumber, Scanner in, PrintWriter out)
        {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        } solve {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        } String s = in.next(); s in.next() in.next in if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            } s.charAt(0) >= 'A' && s.charAt(0) <= 'Z' s.charAt(0) >= 'A' s.charAt(0) s.charAt s 0 'A' s.charAt(0) <= 'Z' s.charAt(0) s.charAt s 0 'Z' {
                out.println('A');
            } out.println('A') out.println out 'A' {
                out.println('a');
            } out.println('a') out.println out 'a' int testNumber testNumber Scanner in in PrintWriter out out public class Main
{
    public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }

    static class Task
    {
        public void solve(int testNumber, Scanner in, PrintWriter out)
        {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        }

    }
} public class Main
{
    public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }

    static class Task
    {
        public void solve(int testNumber, Scanner in, PrintWriter out)
        {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main
{
    public static void main(String[] args)
    {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }

    static class Task
    {
        public void solve(int testNumber, Scanner in, PrintWriter out)
        {
            String s = in.next();
            if (s.charAt(0) >= 'A' && s.charAt(0) <= 'Z')
            {
                out.println('A');
            } else
            {
                out.println('a');
            }
        }

    }
}

