How many 1 characters should appear in the 251 pages of the book.
翻251页书当中要出现多少个1字．
<gadget id="calculator">251 - 1</gadget>
<output>250</output>

<gadget id="calculator">250 / 10</gadget>
<output>25</output>

<gadget id="calculator">25 + 1</gadget>
<output>26</output>

<gadget id="calculator">26 + 30 + 100</gadget>
<output>156</output>

<result>156</result>