FHL is an Austrian fast carrier located in Lienz, whose core business is the transport of palletized load units. The transport service is carried out through five cross$-$docking facilities using two types of trucks. A customer needs to move pallets from two RDCs to three retailers The pallets are classified into two categories, corresponding to liquid food and dry food. The average retailer daily demand in the next trimester is reported in Table $1.$ The quantity of pallets available each day at the RDCs is given in Table $1.$ The transport is generally realized by FHL between each pair of facilities using a single truck with a maximum load of $100$ pallets. Only when the terminal is the retailer, FHL uses larger trucks of $150-$pallet capacity. Due to storage conditions, the small trucks can carry at most $75$ and $55$ pallets of liquid and dry food, respectively. The large trucks cancarry at most $95$ and $75$ pallets of liquid and dry food, respectively. The potential transport network is represented by the directed graph G in Figure $1.$ Each arc corresponds to a potential service from facility i to facility j$.$ The variable costs which are proportional to the number of pallets of the two categories transported; ck$,$ k $1\mathrm{.}2,$ indicates the unit variable transport cost $($in $)$ for each pallet category k$.$ The variable costs are given in Table $2$ Table $1.$ Average daily demand of pallets of the two categories of the products from the three retailers and average daily availability at the two RDC Retailer RDC Categor?