How much postage can be paid with one stamp of 80 cents, one stamp of 1.20 yuan and one stamp of 2 yuan.
用80分、1.20元、2元的邮票各一张，可以支付多少种邮资．
<gadget id="calculator">3 + 3 + 1</gadget>
<output>7</output>

<result>7</result>