! The plants and their capacities ;  
   PLANT1       30			
   PLANT2       25			
   PLANT3       21
~
! The customers and their demands;	
    CUST1            15			
    CUST2            17			
    CUST3            22			
    CUST4            12	
~
! The network arcs and their costs;
    PLANT1 CUST1  2
    PLANT1 CUST2  3
    PLANT1 CUST4  5
    PLANT2 CUST1  2
    PLANT2 CUST2  2
    PLANT2 CUST3  6
    PLANT2 CUST4  5
    PLANT3 CUST2  1
    PLANT3 CUST4  5