September 10 this year is the 28th Teacher's Day. How many years was Teacher's Day established?
今年9月10日是第28个教师节，教师节是多少年设立的．
<gadget id="calculator">2_012 - 28</gadget>
<output>1_984</output>

<gadget id="calculator">1_984 + 1</gadget>
<output>1_985</output>

<result>1_985</result>