n = int(input('Введите число: '))
l = []
с = n
while с > 0:
    l += [с%10]
    с = с//10
s = 0
k = 0
while k < 10:
    s1 = 0
    i = 0
    while i < len(l):
        if l[i] == k:
            s1 = 1
        i += 1
    s += s1
    k += 1
print (s)