temp1(P):- supply(_,P,J1,_), supply(_,P,J2,_), J1 <> J2.
temp2(P):- supply(_,P,J1,_), supply(_,P,J2,_), supply(_,P,J3,_),
           J1 <> J2 , J1 <> J3, J2 <> J3.
answer(P):- temp1(P),not temp2(P).
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