There is a balance with only one weight of 5 grams and one weight of 30 grams. Now it is necessary to divide 300 grams of salt into 3 equal parts, and ask how many times the balance needs to be weighed at least.
有一架天平，只有5克和30克的砝码各一个，现在要把300克盐分成3等份，问最少需要天平称多少次．
<result>3</result>