A number divided by 5 has a remainder of 2, and this number plus 1 is exactly divisible by 7, what is the smallest number.
一个数除以5余2，且这个数再加上1恰能被7整除，这个数最小是多少．
<gadget id="calculator">28 - 1</gadget>
<output>27</output>

<result>27</result>