#!/usr/bin/env python

ans_yes = 0
with open("input01.txt","r") as f:
	answers = ""
	for line in f:
		line = line.strip()
		if len(line) == 0:
			ans_yes += len(set(answers))
			answers = ""
			continue
		answers += line

ans_yes += len(set(answers))
print(ans_yes)