A % B + C - E * F means A is the mother of B, who is the father of C, who is the brother of E,
who is the daughter of F. Thus, C and E are the children of B and F. Since B is the father,
so F is the mother of C and e i.e. F is the wife of B. A is the mother of F's husband i.e.
A is the mother-in-law of F.