assign(domain_size,91).
assign(max_models,-1).
set(arithmetic).

formulas(assumptions).
  Father != 0.	Mother != 0. John != 0.	Ben != 0. Mary != 0.

  abs(Father + -Mother) = abs(John + -Ben).
  abs(Father + -Mother) = abs(Ben + -Mary).
  John * Ben = Father.
  Mary * Ben = Mother.
  Father + Mother + John + Ben + Mary = 90. 
end_of_list.
