888 students lined up in a square to do exercises. Counting from the front to the back, Xiao Ming is the 15th; counting from the left to the right, Xiao Ming is the 30th. Then count from the back to the front, how many is Xiao Ming.
888个同学排成一个方阵做操．从前面往后数，小明是第15个；从左面往右数，小明是第30个．那么从后面往前数，小明是第多少个．
<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<gadget id="calculator">24 - 15</gadget>
<output>9</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<result>10</result>