The price of a schoolbag is 33 yuan. Xiaogang's father has several banknotes of 2 yuan, 5 yuan, and 10 yuan. How many different payment methods are there to buy this schoolbag?
一只书包的售价是33元，小刚的爸爸带有2元、5元、和10元纸币各若干张，要买这只书包，共有多少种不同的付款方式．
<result>6</result>