# Assign 2 - blood type problem  --- extension - with extra constraint

set bloodtypes:= A B O AB;
set donorlinks:= 
        (A,A) (O,A)
        (B,B) (O,B)
        (O,O) 
        (A,AB) (B,AB) (O,AB) (AB,AB) ;
set Olinks:= 
        (O,A)
        (O,B)
        (O,O) 
        (O,AB) ;
set Alinks:= 
        (A,A)
        (A,AB)  ;

param numberpatients:=
 A 5
 B 6
 O 8
 AB 5;

param bloodsupply:=   # the supply is larger than the demand
 A 6
 B 4
 O 14
 AB 4;