import java.util.Scanner;
class Work2{
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String s1 = sc.next();
char s = s1.charAt(0);
if(( s>= 'A' && s<='Z')||(s>='a' && s<= 'z')){
System.out.println("他是字母");
}else{
System.out.println("他不是字母");
}
}
}