题解 | #字符个数统计#

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


// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        int len = str.length();
        if(str=="" || len==0){
            return;
        }
        HashSet<Character> set = new HashSet<Character>();
        for(int i=0; i<len; i++){
            Character c = str.charAt(i);
            int v = Integer.valueOf(c);
            if(v<0 || v>127){
                continue;
            }else{
                set.add(c);
            }
        }
        System.out.println(set.size());
    }
}