题解 | #字符个数统计#

import java.util.*;

// 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);
        while (sc.hasNextLine()){
            String line = sc.nextLine();
            String[] inStr = line.split("|");
            // Set<String> charSet = Arrays.stream(inStr).collect(Collectors.toSet());
            Set<String> charSet = new HashSet<>();
            for(int i = 0;i<inStr.length;i++){
                charSet.add(inStr[i]);
            }
            System.out.println(charSet.size());
        }
    }
}