s = str(input())
p = []
i = 0
while(i < len(s)):
    c = s[i]
    while(c in p):
        i += 1
        if(i == len(s)-1):
            c += s[-1]
        else:
            c += s[i]
    p.append(c)
    i += 1
print(len(p))