244-726 6 times

Law: First, divide it into three parts on average, the number of times needed is 3 to the n power, and 3 to the n power is the maximum number of terms. Secondly, dividing it into three parts on average can always ensure that the quantity will be reduced quickly, because if you compare two parts and leave one, you will definitely find the part where the defective product is, and continue to divide it into three parts on average, which is still the case now. So there are all three.