"Here's the next one," Said the detective.

He held up the piece of paper.

A list of people who attended the family reunion:

One Grandfather.

One grandmother.

Two fathers.

Two mothers.

Four children.

Three grandchildren.

One brother.

Two sisters.

Two sons.

Two daughters.

One father-in-law.

One mother-in-law.

One daughter-in-law.

How many people were there really?