def char_type_count(str):
    string = "".join(set(str)) # 去重之后连接成新的字符串
    count = 0
    for i in string:    # 遍历string
        if 0 <= ord(i) <= 127:  # ord(i)代表i的ascii码的值
            count += 1
    print(count)

char_type_count(input())    # 直接调用这个函数