题解 | #完全数计算#

import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class Main {
 
    public static void main(String[] args)throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        int[] charNum = new int[128];
        for (char c : str.toCharArray()) {
            charNum[c]++;
        }
        int sum = 0;
        for (int i : charNum) {
            if (i != 0) {
                sum++;
            }
        }
        System.out.println(sum);
    }
 
}