In Snape’s potions class, he gives Harry 35 ounces of dragon’s blood, and 49 ounces of ground spider’s legs. Snape tells him to use all of the ingredients to create several batches of a new potion. Snape tells him that every cauldron must have the same amount of each ingredient, and that he must not have any leftovers. What is the largest number of cauldrons that Harry can make?