A kind of red ink has two different specifications: 3 bottles and 4 bottles. Director Liu wants to buy 42 bottles of red ink. How many different ways are there in total?
一种红墨水有3瓶装和4瓶装两种不同规格的包装，刘主任要购买42瓶红墨水，一共有多少种不同的购买方法？
<result>4</result>