Beware that the function in prop. may take the values 0 or 1 even outside of the two subsets.
Choo nọmba pere mpe iji tọghata nọmba ahụ nyere na 0. perform nwere ike ịrụ nke ọ bụla n'ime abụọ, ma wepu 1 ma ọ bụ kewaa integer site na 2.