An old woman took out 10 yuan to buy stamps at the post office. She asked to buy several stamps of 5 cents, and then bought stamps of 2 cents. The number of stamps of 2 cents was five times that of stamps of 5 cents, and the remaining money bought stamps of 8 cents. How many stamps did you buy in total?
一位老妇在邮局拿出10元买邮票．她要求买若干枚5角的邮票，再买2角的邮票，2角邮票的数量为5角邮票的5倍，余下的钱买8角的邮票，刚好把钱用完，那么这位老妇共买邮票多少枚．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">4 + 20 + 5</gadget>
<output>29</output>

<result>29</result>