It is actually quite simple. You have to drink 1 serving of juice ( 100-120 Cal) 4 times a day.Therefore...400-480 cal per day comes from juice.
The LA TO juice is 1 serving = 125ml ( 100 cal) and you have to dilute it by a adding 125 ml water. Because water is 0 cal...you get a 250 ml/8 oz drink per 100 cal.This you drink 4 times...therefore 32 oz.
Some juices, eg. Kiju juice boxes are only 100 cal per 250 ml/8 oz box. Therefore there is no need to add water.So whatever juice you drink...whether you dilute or not shoot for 100-120 cal per serving.