题解 | #字符个数统计#

import java.util.HashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        HashSet<Character> hSet = new HashSet<Character>();
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            if (c <= 127 && c >= 0) {
                hSet.add(c);
            }        
        }
        System.out.print(hSet.size());
    }
}