man(kondratyev).
man(davydov).
man(fyodorov).

occupation(malyar).
occupation(stolyar).
occupation(vodoprovodchick).

knows(_,_).
solve(Solve):-
  Solve = [person(X, Xoccupation), person(Y, Yoccupation),
          person(Z, Zoccupation)],

  man(X), man(Y), man(Z),
  X\=Y,X\=Z,Y\=Z,

  occupation(Xoccupation), occupation(Yoccupation), occupation(Zoccupation),
  Xoccupation\=Yoccupation,Xoccupation\=Zoccupation,Yoccupation\=Zoccupation,

  knows(member(person(StolyarName, stolyar), Solve), member(person(MalyarName, malyar), Solve)),
  knows(member(person(StolyarName, stolyar), Solve), member(person(VodoprovodName, vodoprovodchick), Solve)),
  not(knows(member(person(fyodorov, FyodorovJob), Solve), member(person(davydov, DavydovJob), Solve))),
  knows(member(person(MalyarName, malyar), Solve), member(person(StolyarName, stolyar), Solve)),
  knows(member(person(VodoprovodName, vodoprovodchick), Solve), member(person(StolyarName, stolyar), Solve)),
  not(knows(member(person(davydov, DavydovJob), Solve), member(person(fyodorov, FyodorovJob), Solve))).