import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (sc.hasNext()) {
String next = sc.next();
Set<String> charSet = new HashSet<>();
char[] chars = next.toCharArray();
for (char aChar : chars) {
charSet.add(String.valueOf(aChar));
}
System.out.println(charSet.size());
}
}
}
import java.util.Scanner;
import java.util.Set;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (sc.hasNext()) {
String next = sc.next();
Set<String> charSet = new HashSet<>();
char[] chars = next.toCharArray();
for (char aChar : chars) {
charSet.add(String.valueOf(aChar));
}
System.out.println(charSet.size());
}
}
}