If A∩B contains 'p' elements and A∩C contins 'q' elements, then find (q-p)

Question

Let A = {(x,y) : x∈R, y∈R, x^3 + y^3 = 1}, B = {(x,y) : x∈R, y∈R, x-y=1} and C = {(x,y) : x∈R, y∈R, x+y=1}. If A∩B contains 'p' elements and A∩C contins 'q' elements, then find (q-p)