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 sc = new Scanner(System.in);
        while(sc.hasNext()){
            String str = sc.nextLine();
            char[] arr = str.toCharArray();
            HashSet<Character> hashS = new HashSet<>();
            int count = 0;
            for (int i = 0; i < arr.length; i++) {
                if(arr[i] >= 0 && arr[i] <= 127){
                    if (hashS.add(arr[i])){
                        count++;
                    }
                }
            }
            System.out.println(count);

        }

    }
}