import java.util.*;
import java.io.*;
public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        char arr[]=br.readLine().toCharArray();
        if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a");
        pw.flush();
        pw.close();
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        char arr[]=br.readLine().toCharArray();
        if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a");
        pw.flush();
        pw.close();
    }
} Main public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        char arr[]=br.readLine().toCharArray();
        if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a");
        pw.flush();
        pw.close();
    } main {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        char arr[]=br.readLine().toCharArray();
        if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a");
        pw.flush();
        pw.close();
    } BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) PrintWriter pw=new PrintWriter(System.out); pw new PrintWriter(System.out) char arr[]=br.readLine().toCharArray(); arr br.readLine().toCharArray() br.readLine().toCharArray br.readLine() br.readLine br if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a"); arr[0]>='A'&&arr[0]<='Z' arr[0]>='A' arr[0] arr 0 'A' arr[0]<='Z' arr[0] arr 0 'Z' pw.println("A") pw.println pw "A" pw.println("a") pw.println pw "a" pw.flush() pw.flush pw pw.close() pw.close pw String ars[] ars public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        char arr[]=br.readLine().toCharArray();
        if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a");
        pw.flush();
        pw.close();
    }
} public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        char arr[]=br.readLine().toCharArray();
        if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a");
        pw.flush();
        pw.close();
    }
} Main
import java.util.*;
import java.io.*;
public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        char arr[]=br.readLine().toCharArray();
        if(arr[0]>='A'&&arr[0]<='Z')
        pw.println("A");
        else
        pw.println("a");
        pw.flush();
        pw.close();
    }
}