need an excel formula or macro vba code to auto calculate the material requirement. for example: if the "Days of Stock" in july is >= to 30 days then the "requirement" in june should be 0 but if the "Days of Stocks" is less than 30 days then the "requirement" in june should equal the "demand" in july.

B D E E F G H 1 Jun Jul Aug Oct Nov Dec Sep 56 44 1980 1305 322 (1311) (1890) (2758) 45 2 821 0 0 0 0 0 46 0 0 1500 0 0 0 0 47 22012787 5.5 L80 LTC API 10th In Transit PO's Requirement Demand Ending Inventory Days of Stock 48 1496 983 1766 1367 579 868 740 49 1305 322 56 (1311) (1890) (68) (2758) (65) (3498) (112) 50 54 44 5 1