If the first bench seats 4 students, there will be no place for 3 students to sit, and if the first bench seats 5 students, there will be 2 empty seats. How many students are there?
如果第一个长椅子坐4位学生，就有3名学生没地方坐，如果第一个长椅子坐5位学生，就有2个空座位．有多少个学生．
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">5 / 1</gadget>
<output>5</output>

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

<gadget id="calculator">20 + 3</gadget>
<output>23</output>

<result>23</result>