题解 | #字符个数统计#

import java.util.BitSet;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		BitSet bset = new BitSet(128);
		String s = sc.next();
		for(char c : s.toCharArray()){
			bset.set(c);
		}
		System.out.println(bset.cardinality());
		
		sc.close();
	}
}