import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        char c = 'A';
        boolean f = false;
        for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        }

        System.out.println(f?"A":"a");
    }

} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        char c = 'A';
        boolean f = false;
        for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        }

        System.out.println(f?"A":"a");
    }

} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        char c = 'A';
        boolean f = false;
        for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        }

        System.out.println(f?"A":"a");
    } main {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        char c = 'A';
        boolean f = false;
        for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        }

        System.out.println(f?"A":"a");
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String a = sc.next(); a sc.next() sc.next sc char c = 'A'; c 'A' boolean f = false; f false for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        } int i=0; int i=0; i 0 i<26 i 26 i++ i++ i {
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        } {
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        } if(String.valueOf(c).equals(a)){
                f = true;
                break;
            } String.valueOf(c).equals(a) String.valueOf(c).equals String.valueOf(c) String.valueOf String c a {
                f = true;
                break;
            } f = true f true break; c++ c System.out.println(f?"A":"a") System.out.println System.out System System.out f?"A":"a" f "A" "a" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        char c = 'A';
        boolean f = false;
        for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        }

        System.out.println(f?"A":"a");
    }

} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        char c = 'A';
        boolean f = false;
        for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        }

        System.out.println(f?"A":"a");
    }

} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String a = sc.next();
        char c = 'A';
        boolean f = false;
        for(int i=0;i<26;i++){
            if(String.valueOf(c).equals(a)){
                f = true;
                break;
            }
            c++;
        }

        System.out.println(f?"A":"a");
    }

}
