题解 | #字符个数统计#

while True:
    try:
        list1 = list(input())
        a = len(list1)
        j = 0
        list2 = []
        for i in range(a):
            if list1[j] in list2:
                j += 1
            else:
                list2.append(list1[j])
                j += 1
        print(len(list2))
    except:
        break