Minimum Bottles

There are $N$ identical water bottles, each of which has a capacity of $X$ liters. The $i^{th}$ bottle initially contains $A_i$ liters of water. You want to go on a trip and want to carry **all** your water with you. However, to not make packing a hassle, you also want to carry the least number of bottles with you. You can transfer any amount of water from one bottle to another, provided t