RIDDLE

2 barrels A and B, contain unspecified amounts of cider, A containing more than B. From A, pour into B and much as B already contains, Then, from B, pour into A as much cider as A now contains. Finally pour from A into B as much cider as B presently has. Both barrels now contain 64 liters of cider. How many liters were in each barrel at the start of the process?