--- Part Two ---

As you finish the last group's customs declaration, you notice that you misread one word in the
instructions:

You don't need to identify the questions to which anyone answered "yes"; you need to
identify the questions to which everyone answered "yes"!

Using the same example as above:

abc

a b c

ab ac

a a a a

b

This list represents answers from five groups:

- In the first group, everyone (all 1 person) answered "yes" to 3 questions: a, b, and
c. - In the second group, there is no question to which everyone answered "yes". - In
the third group, everyone answered yes to only 1 question, a. Since some people did not
answer "yes" to b or c, they don't count. - In the fourth group, everyone answered yes to only
1 question, a. - In the fifth group, everyone (all 1 person) answered "yes" to
1 question, b.

In this example, the sum of these counts is 3 + 0 + 1 + 1 + 1 = 6.

For each group, count the number of questions to which everyone answered "yes".
What is the sum of those counts?