import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc =new Scanner(System.in);
    String S =sc.next();
    String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    }
    System.out.println("a");
  }
} import java.util.*; util.* java public class Main{
  public static void main(String[] args){
    Scanner sc =new Scanner(System.in);
    String S =sc.next();
    String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    }
    System.out.println("a");
  }
} Main public static void main(String[] args){
    Scanner sc =new Scanner(System.in);
    String S =sc.next();
    String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    }
    System.out.println("a");
  } main {
    Scanner sc =new Scanner(System.in);
    String S =sc.next();
    String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    }
    System.out.println("a");
  } Scanner sc =new Scanner(System.in); sc new Scanner(System.in) String S =sc.next(); S sc.next() sc.next sc String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"}; T {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"} "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" "T" "U" "V" "W" "X" "Y" "Z" for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    } int i=0; int i=0; i 0 i<26 i 26 i++ i++ i {
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    } {
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    } if(S.equals(T[i])){System.out.println("A");System.exit(0);} S.equals(T[i]) S.equals S T[i] T i {System.out.println("A");System.exit(0);} System.out.println("A") System.out.println System.out System System.out "A" System.exit(0) System.exit System 0 System.out.println("a") System.out.println System.out System System.out "a" String[] args args public class Main{
  public static void main(String[] args){
    Scanner sc =new Scanner(System.in);
    String S =sc.next();
    String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    }
    System.out.println("a");
  }
} public class Main{
  public static void main(String[] args){
    Scanner sc =new Scanner(System.in);
    String S =sc.next();
    String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    }
    System.out.println("a");
  }
} Main
import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc =new Scanner(System.in);
    String S =sc.next();
    String T[] ={"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
    for(int i=0;i<26;i++){
      if(S.equals(T[i])){System.out.println("A");System.exit(0);}
    }
    System.out.println("a");
  }
}
