#!/bin/python

ALL_ANSWERS = set([i for i in "abcdefghijklmnopqrstuvwxyz"])

with open("input", "r") as input:
    sum = 0
    answers = set(ALL_ANSWERS)
    for line in input:
        line = line.strip()
        if line == "":
            sum += len(answers)
            answers = set(ALL_ANSWERS)
            continue

        answers = answers.intersection(set([char for char in line]))

    
    sum += len(answers)
    print(sum)