At a recent family reunion, the family consisted of

At a recent family reunion, the family consisted of
1 grandfather, 1 grandmother, 2 fathers, 2 mothers, 4 children,
3 grandchildren, 1 brother, 2 sisters, 2 sons, 2 daughters,
1 father-in-law, 1 mother-in-law, and 1 daughter-in-law.
How many minimum no. of people at the reunion?