Given below is the pipeline network of XYZ Refineries Ltd., which supplies oil to ten depots – A through J – of the company. Each connecting pipeline has a maximum capacity of 750 kilolitres per minute (750 klpm). The slack in any pipeline is defined as the extra flow required in it to bring it to full capacity. In each pipeline, the oil can flow only in the direction indicated by the arrow, as shown in the figure.

Except for node XYZ, every depot has a certain requirement of oil, mentioned (in klpm) alongside in the figure. For none of the ten depots, the requirement is less than 50 klpm. Only if the requirement at a depot is fully met is the remaining oil, if any, passed on to the next depot connected to it. Further, it is known that the requirements at all the depots are exactly met and that none of the three pipelines connecting XYZ to A, D, and B, respectively, have any slack in them.

What is the slack (in klpm) in the pipeline connecting depots B and E?