# -*- coding: utf_8 -*-

import codecs

merkkilista = {}

file = codecs.open("jee.txt", "r", "utf-8")

laskuri = 0

while 1:
    char = file.read(1)
    if not char: break
    if char not in merkkilista:
        laskuri = laskuri + 1
        merkkilista[char] = laskuri
print laskuri - 1